Process for improving carbon black dispersion

ABSTRACT

A masterbatch comprising pigment and demolding agent is provided. The demolding agent is selected from the group comprising low molecular weight polyolefin oils, low molecular weight polyolefin waxes, montan waxes and aliphatic or aromatic carboxylic acid esters of fatty acids and/or fatty alcohols, wherein the pigment content of the masterbatch is from 3 to 70 wt. %, based on the total weight of the masterbatch. The masterbatch is suitable for preparation of a polymer composition having improved pigment dispersion.

CROSS REFERENCE TO RELATED APPLICATION

This application Application is a reissue of U.S. application Ser. No.13/332,047, filed on Dec. 20, 2011, issued as U.S. Pat. No. 9,056,957,which claims priority to European Patent Application No. 10196932.7,filed Dec. 23, 2010, the content of each of which is incorporated hereinby reference in its entirety.

BACKGROUND

1. Field of the Invention

The invention provides pigment-containing polycarbonate compounds havingimproved dispersion of the pigment particles in the polymer matrix, anda process for the preparation of these compounds. Carbon black ispreferably used as the pigment, “carbon black” in the present inventionrepresenting all particulate pure carbon substrates and carboncompounds, for example colour carbon blacks, conductivity carbon blacks,carbon nanotubes, graphite. The pigment-containing polycarbonatecompounds can contain further polymers, such as, for example, elastomersor graft polymers, or further thermoplastics, such as, for example,polyesters.

The present invention relates further to the use of pigmentmasterbatches containing the pigment and a demoulding agent which is tobe added to the polycarbonate composition.

The present invention relates further to a process for the preparationof such polycarbonate compounds having improved dispersion of thepigment particles in the polymer matrix, in which, in the compounding ofthe polycarbonate composition, a masterbatch of the pigment in fattyacid esters based on aliphatic alcohols or polyols is used. Theinvention further provides the preparation of such pigment masterbatchesin fatty acid esters.

2. Description of Related Art

A technical problem when incorporating pigments, and carbon blackparticles in particular, into thermoplastic polymer compositions is thatof dispersing the pigment particles completely and uniformly in thepolymer matrix. Incompletely dispersed pigment particles form pigmentagglomerates which apart from colour inhomogeneities and inadequatedepth of colour also result in particular in defects which have anadverse effect on the mechanical properties of the polymer compositions,such as their strength and ultimate elongation, and also on the surfaceproperties of the materials. Larger pigment agglomerates lead, forexample, to faults and defects on the surface of such compositions suchas pitting, streakiness and, ultimately, to an undesirable reduction inthe degree of gloss. In a composite with other materials, such surfacedefects can additionally also adversely affect the composite adhesionproperties (for example lacquer adhesion).

Carbon-based pigments—such as, for example, carbon blacks, graphites,fullerenes, graphenes, activated charcoals and carbon nanotubes, whichare used in many commercial fields of application, for example for blackcolouration, for increasing the electrical or thermal conductivity ofthe composition, for mechanical strengthening or also for binding andreducing the volatility of low molecular weight organic compounds suchas residual monomers or odour-bearing substances are distinguished byparticularly strong interparticle binding forces and therefore have aparticularly high tendency to form agglomerates, which can be broken upagain only with difficulty on incorporation into thermoplastic polymers.

Various methods are known from the prior art for improving thedispersion of such pigments in thermoplastic polymer compositions. Forexample, pigment dispersion can be improved by increasing the specificenergy input by means of shear during the incorporation of the pigmentsinto the polymer melt in conventional compounding units such astwin-screw extruders or internal kneaders.

However, the energy input which can be used for pigment dispersion istechnically limited in the case of polymer melts, in particular thosehaving a low viscosity, that is to say high melt flowability, as isrequired for good thermoplastic processability in most fields ofapplication. In other cases, the energy input is limited by the thermalloading capacity of the polymer melt into which the pigment is to beincorporated. High specific energy inputs naturally lead to high processtemperatures which, depending on the polymer, can lead to undesirabledamage, ageing or even decomposition of the polymer.

A further method is the use of a highly concentrated masterbatch of thepigment in a polymer matrix, but the technically achievableconcentration of the pigment in the polymer matrix is not high enoughfor an economic application without the use of furtheradditives/processing aids. Furthermore, good pigment dispersion in theend product can be achieved with this method only if the pigments arealready well dispersed in the masterbatch, which is only insufficientlyensured when using polymer matrices, in particular in polycarbonate.

A further possibility for improving the dispersion of pigments consistsin using dispersing aids, which reduce the intermolecular interactionsbetween the individual pigment particles or pigment aggregates within apigment agglomerate and thereby facilitate the breaking up of theagglomerates during the preparation of the compounds. The disadvantageof the use of such dispersing aids, which have no other necessary actionin the composition, is that they remain in the polymer composition thatis produced and, as a result, may possibly adversely affect theapplication-related properties of the target products.

For example, such dispersing aids in multiphase compositions (blends) ofdifferent polymers (such as, for example, impact-modified polymers) canadversely affect the phase compatibility of the different polymercomponents by accumulating at the phase boundaries and thereby adverselyaffect the mechanical properties of the blend composition. Likewise,these additives can catalyse undesirable ageing processes in certainpolymer systems, for example hydrolytic decomposition reactions inpolycondensation polymers.

The preparation of pigment concentrates in wax-like compounds is alreadyknown from U.S. Pat. No. 4,484,952, wherein the preparation of carbonblack concentrates in PETS (pentaerythritol tetrastearate) is alsodescribed. However, the shear forces which occur under the stirring,spraying or centrifugation conditions mentioned in U.S. Pat. No.4,484,952 for mixing the pigments with the carrier are too small toachieve sufficiently fine separation and uniform distribution of thepigments in the carrier material in the case of highly agglomeratedpigments. However, this is a necessary requirement for subsequentuniform dispersion of the pigments in a polymer matrix with the aid ofsuch pigment concentrates. Moreover, U.S. Pat. No. 4,484,952 gives noindication of the quality of the pigment dispersion which can beachieved in thermoplastics with carbon black concentrates so prepared,in particular the dispersion of the carbon black which can be achievedin polycarbonate compositions. Furthermore, there is no information inU.S. Pat. No. 4,484,952 regarding the process parameters used in thepreparation of the pigment concentrates and the energy input as well asthe mixing unit used, which have a critical influence on the quality ofthe dispersion.

The preparation of pigment and, in particular, carbon black concentratesin wax-like compounds is also known from U.S. Pat. No. 4,310,483.However, this is likewise a concentrate form in which only a low energyinput for the separation of agglomerated pigments and their uniformdistribution in the matrix material occurs. The preparation process isin fact aimed at improving the metering properties of the describedpigment concentrates, dust formation being largely avoided and a moreadvantageous metering form being achieved by wetting of the pigments.The amount of pigment in the described carbon black concentrates farexceeds the amount of granulating aid used. Regarding the quality of thepigment dispersion in thermoplastics using such pigment concentrates, itis stated in U.S. Pat. No. 4,310,483 that it is equally as good as inthe case of the metering of pure powder without the use of granulatingaids, but an improvement in the dispersion is not described.

WO 2002/092702 relates to the coating of carbon black pellets byspraying with wax-like compounds, accordingly, for example, also withPETS, in order to improve the metering properties of carbon blackproducts by the coating.

The preparation of carbon black-containing polycarbonate mouldingcompositions using carbon black masterbatches is described in EP 578 245A2. However, the masterbatches here are masterbatches in polyethylenes.Polyethylenes lead to disadvantageous property changes in polycarbonatemoulding compositions, for example in respect of the low-temperaturestrength of the moulding compositions, and are therefore to be avoided.

US 2009/0057621 A1 describes the melt-mixing of carbon-containingthermoplastic masterbatches with thermoplastics without isolation of themasterbatch but with simultaneous continuous metering into a secondthermoplastic melt, wherein the thermoplastic can also be polycarbonate.Such a process is technically too complex and inflexible, however.

SUMMARY

In order to overcome disadvantages associated with the above-mentionedart, it was, therefore, an object of the present invention to provide anovel process for improved dispersion of pigments, in particular carbonblack, in polycarbonate compounds.

In addition, when using pigment concentrates, no foreign substances thatdo not have a necessary action in the composition are to be introducedinto the polycarbonate compounds.

Furthermore, a pigment concentrate in isolated form is to be provided,which concentrate is suitable for incorporation into and for thepreparation of polycarbonate compounds having improved pigmentdispersion.

It was a further object of the invention, by the use of a pigmentconcentrate, to achieve better dispersion of pigments in a polymermatrix than is possible by metering the pure pigment in powder form in asingle compounding step, it still being possible to carry out thepreparation process under standard conditions in conventional mixingunits such as, for example, in single- or multi-shaft extruders,kneaders or internal mixers.

Surprisingly, it has been found that pigments, in particular carbonblacks, in substances which are used as demoulding agents forpolycarbonate moulding compositions, in a preferred embodiment inaliphatic fatty acid esters, can, under defined conditions, be bothhomogenously distributed and very well dispersed in the melt of thefatty acid esters using mechanical shear, and that a carbon blackconcentrate so prepared, after cooling, can be formed into pellets andused in a subsequent compounding process as a masterbatch for colouringthermoplastic compositions, in particular also for colouringpolycarbonate compositions. In principle, various types of demouldingagents and various, in particular carbon-containing, pigments aresuitable for the preparation of such masterbatches.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structure of a co-kneader.

FIG. 2 shows a structure of a co-kneader without a retaining ring.

FIG. 3 shows a structure of a co-kneader with a metering hopper.

FIG. 4 shows a structure of an extruder with a length-to-diameter ratioof 44.

FIG. 5 shows a structure of an extruder with a length-to-diameter ratioof 36.

FIG. 6 shows a structure of an extruder with an injection valve.

FIG. 7 shows a structure of an extruder with a length-to-diameter ratioof 48.

FIG. 8 shows a structure of an extruder with a length-to-diameter ratioof 31.5.

FIG. 9 shows a structure of an extruder with a length-to-diameter ratioof 40.

FIG. 10 shows a graph.

FIG. 11 shows a diagram of the process parameters of an extruderdenoting notched impact strength at an ambient temperatures of 260° C.

FIG. 12 shows a diagram of the process parameters of an extruderdenoting notched impact strength at an ambient temperatures of 300° C.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Objects of the present invention can be achieved, for example, by thecompositions, the process and the use as disclosed hereinbelow anddescribed in the claims, the preferred embodiments according to theinvention generally being described hereinbelow with carbon black as thepreferred pigment by way of example, but this does not imply anyfundamental limitation to carbon black as the pigment.

Concentrates of suitable carbon black types in demoulding agentscontaining fatty acid esters were prepared, which concentrates canpreferably be granulated at room temperature. The demoulding agent thatis preferably used for the preparation of such carbon blackmasterbatches is pentaerythritol tetrastearate (PETS). However, otherfatty acid esters, preferably those which are solid at room temperature(20° C.), can likewise be used for the preparation of carbon blackmasterbatches according to the invention. The carbon black masterbatchesaccording to the invention can be prepared in conventional compoundingunits in the melt of the fatty acid esters with the application ofsufficiently high shear energy for the adequate separation of anyagglomerated carbon black particles.

It has further been found that polycarbonate moulding compositions whichhave been prepared and coloured using the carbon black masterbatchesaccording to the invention by compounding in a single compounding stepin conventional mixing units such as, for example, single- ormulti-shaft extruders, kneaders or internal mixers under standardconditions, exhibit substantially improved dispersion of the carbonblack particles in the polycarbonate matrix after thermoplasticprocessing to moulded articles. The polycarbonate moulding compositionscan contain further thermoplastics or particulate elastomeric polymers,as well as conventional fillers and polymer additives.

Accordingly, the invention provides, in particular, a process for thepreparation of carbon black-containing polycarbonate mouldingcompositions, wherein the carbon black is present in finely dispersedform in the form of a masterbatch in a substance which is used asdemoulding agent in the formulation of the polycarbonate mouldingcompositions and accordingly exhibits a necessary action in thecomposition, and is introduced into the polycarbonate mouldingcomposition by melt compounding. The carbon black masterbatch ispreferably in the form of a pellet, as described above, and is used andmetered as such in the compounding process. As an alternative, however,such a carbon black masterbatch, because of the low melt viscosity atthe relatively low melting points, can also be fed into the compoundingunit in liquid or pasty form with the aid of melt metering pumps.

Suitable mixing units for the preparation of the carbon blackmasterbatch are single- or multi-shaft extruders or kneaders, such as,for example, Buss co-kneaders or internal mixers or shear rollers, andany mixing units with which a sufficiently high shear energy can beintroduced into the melt of carbon black and demoulding agent in orderto finely separate any solid carbon black agglomerates and distributethem uniformly in the demoulding agent.

The starting components carbon black and demoulding agent are fed to thecompounding unit either separately or in the form of a powder or grainor granule mixture and are intimately mixed in the melt at a heatingtemperature of the housing of from 25° C. to 200° C., preferably from30° C. to 130° C.

The masterbatches so obtained, depending on their carbon black contentand the demoulding agent used, preferably have a solid consistency atroom temperature. For metering in the form of a solid, the carbon blackmasterbatches are formed into melt strands, optionally filtered in themelt through a fine-mesh sieve (10-100 μm mesh size, preferably 20-50μm) in order to retain incompletely separated carbon black agglomerates,and then cooled to temperatures below 40° C., preferably below 30° C.,and subsequently granulated.

Suitable granulating devices for the preparation of sufficiently finelydivided granules/pellets of the carbon black masterbatch which canreadily be metered in the subsequent compounding of the polycarbonatemoulding compositions are underwater or hot-face water-ring granulators.The granules or pellets so obtained have a maximum length of preferably8 mm, particularly preferably not more than 5 mm, and a minimum lengthof preferably 0.5 mm, particularly preferably not less than 1 mm, thelength defining the axis in the direction of the greatest extent of abody.

In an alternative embodiment, the masterbatch is used in the form of apowder having a maximum diameter smaller than 0.5 mm and not less than0.1 mm.

The amount of carbon black or pigment in the masterbatch can vary withinrelatively wide limits from 3 wt. % to 70 wt. %, based on themasterbatch; the carbon black content is preferably from wt. % to 70 wt.%, more preferably from 35 wt. % to 65 wt. %, particularly preferablyfrom 40 to 60 wt. %.

The nature of the pigment used and in particular also of the carbonblack used can vary very greatly, the term “carbon black” also includingchemical species such as carbon nanotubes, graphite, conductivity carbonblack and colour carbon black, as well as carbon blacks obtained by verydifferent production processes. Colour carbon blacks and conductivitycarbon blacks are particularly preferred, and colour carbon blacks aremost particularly preferred. These carbon blacks can optionally also beused together with other organic or inorganic pigments either in thecarbon black masterbatch or in the compounding of the polycarbonatemoulding composition. Carbon nanotubes (CNTs) are preferably not used inan alternative embodiment.

The nature of the demoulding agent used can likewise vary greatly, therepreferably being used compounds such as low molecular weight polyolefinoils or waxes, hydrogenated oils, montanic acid or fatty acid esters,which preferably have a solid consistency at room temperature. Furtherpreferred demoulding agents are aliphatic montanic or fatty acid esters,such as, for example, glycerol stearates or palmitates orpentaerythritol stearates. Pentaerythritol tetrastearate (PETS) isparticularly preferred.

These carbon black masterbatches prepared according to the invention areintimately mixed with polymers, preferably with polycarbonate andoptionally further components of the polymer, preferably polycarbonate,moulding composition in conventional melt-mixing units, such as, forexample, in single- or multi-shaft extruders or in kneaders, in the meltunder conventional conditions, and the mixture is extruded andgranulated. They can be metered at a suitable location into the solidsfeed region of the extruder or into the polymer melt, either separatelyin the form of granules or pellets via proportioning weighers or lateralfeed devices or alternatively at elevated temperature in the form of amelt by means of metering pumps. The masterbatches in the form ofgranules or pellets can also be combined with other particulatecompounds to give a premixture and then fed together into the solidsfeed region of the extruder or into the polymer melt in the extruder viametering hoppers or lateral feed devices. The compounding unit ispreferably a twin-shaft extruder, particularly preferably a twin-shaftextruder having co-rotating shafts, the twin-shaft extruder having alength/diameter ratio of the screw shaft of preferably from 20 to 44,particularly preferably from 28 to 40. Such a twin-shaft extrudercomprises a melting and mixing zone or a combined melting and mixingzone (this “melting and mixing zone” is also referred to hereinbelow asthe “kneading and melting zone”) and optionally a degassing zone inwhich an absolute pressure p_(abs) of preferably not more than 800 mbar,more preferably not more than 500 mbar, particularly preferably not morethan 200 mbar, is set. The mean residence time of the mixturecomposition in the extruder is preferably limited to not more than 120s, particularly preferably not more than 80 s, particularly preferablynot more than 60 s. In a preferred embodiment, the temperature of themelt of the polymer or of the polymer alloy at the extruder outlet isfrom 200° C. to 400° C.

The invention accordingly also provides pigment-containing polymermoulding compositions, in a preferred embodiment polycarbonate mouldingcompositions, having improved pigment dispersion, which mouldingcompositions are prepared by the process according to the invention,that is to say using a pigment-demoulding agent concentrate according tothe invention containing

-   -   a) from 1 to 99.96 wt. %, preferably from 40 to 99.9 wt. %, more        preferably from 50 to 99.8 wt. %, particularly preferably from        50 to 75 wt. %, of at least one thermoplastic polymer (a),    -   b) from 0.02 to 10 wt. %, preferably from 0.05 to 5 wt. %, more        preferably from 0.1 to 3 wt. %, particularly preferably from 0.1        to 1.5 wt. %, of at least one pigment component (b), in a        preferred embodiment of a carbon-based pigment, in a        particularly preferred embodiment carbon black,    -   c) from 0.02 to 10 wt. %, preferably from 0.05 to 5 wt. %, more        preferably from 0.1 to 3 wt. %, particularly preferably from 0.1        to 1.5 wt. %, of at least one demoulding agent (c),    -   d) from 0 to 70 wt. %, preferably from 0 to 60 wt. %, more        preferably from 2 to 60 wt. %, particularly preferably from 20        to 60 wt. %, of one or more thermoplastic polyesters (d),    -   e) from 0 to 50 wt. %, preferably from 0 to 40 wt. %, more        preferably from 1 to 30 wt. %, particularly preferably from 2 to        20 wt. %, of one or more elastomers (e) other than component    -   f) from 0 to 70 wt. %, preferably from 0 to 60 wt. %, more        preferably from 1 to 50 wt. %, particularly preferably from 3 to        40 wt. %, of one or more optionally rubber-modified vinyl        (co)polymers (f), and    -   g) from 0 to 40 wt. %, preferably from 0 to 30 wt. %, more        preferably from 0.1 to 20 wt. %, particularly preferably from        0.2 to 10 wt. %, of further additives.

Components b and c can be used in the preparation of thepigment-containing polymer moulding compositions according to theinvention either wholly or only partially in the form of a masterbatchof components b and c. In a preferred embodiment, carbon-based pigmentsaccording to component b are used in the preparation of thepigment-containing polymer moulding compositions according to theinvention solely in the form of a masterbatch of components b and c, itbeing possible, however, for a portion of component c in this preferredembodiment also to be used in the form of the pure component in thepreparation of the pigment-containing polymer moulding compositionsaccording to the invention. In a particularly preferred embodiment,components b and c are used in the preparation of the pigment-containingpolymer moulding compositions according to the invention solely in theform of a masterbatch of components b and c.

Moulded articles which have been produced by thermoplastic processing,for example by injection moulding, from these pigment/carbonblack-containing polymer/polycarbonate moulding compositions preparedaccording to the invention exhibit a markedly more homogeneous mouldingsurface with markedly fewer optical imperfections, that is to saysurface defects, and markedly improved strength, in particular improvednotched impact strength, as compared with polymer/polycarbonate mouldingcompositions of the same composition which have been prepared by directcompounding, for example from powder mixtures or by compounding usingthermoplastic-based pigment/carbon black masterbatches.

In a preferred embodiment, the number of surface defects (pitting,craters, pinholes, etc.) on moulded articles produced by the injectionmoulding process from the polymer/polycarbonate compositions accordingto the invention is reduced by at least 20%, particularly preferably by20 to 95 percent, as compared with moulded articles of the mouldingcompositions having the same composition which have been prepared by adifferent process, in particular by a one-step compounding process usingpigment component b in powder form.

The surface defects of injection-moulded articles produced on injectionmoulding tools with a high-gloss finish (ISO N1) can be identified andquantified by optical analysis methods, all imperfections having a meandiameter of at least 10 min being used in determining the number ofsurface defects. The number of surface defects was determined byobserving the moulding surfaces under a reflected light microscope—e.g.Zeiss Axioplan 2 motorised—through an object lens with 2.5×magnification in a bright field, with illumination by means of a halogen100 light source. The number of defects in a surface region measuring 4cm×4 cm was determined by scanning the area in a meandering manner. Thedetermination was assisted by a camera—e.g. Axiocam IRC—with imageevaluation software—e.g. KS 300 Zeiss.

According to analysis by Raman spectroscopy, the surface defects thusdetermined optically on mouldings of polymer/polycarbonate mouldingcompositions having the above-mentioned compositions representagglomerates and aggregates of pigments, in particular carbon blackparticles, optionally together with elastomer particles of components Eand/or F, which are inadequately separated in the melt compounding ofthe components in the extruder. Such surface defects are clearly visibleby reflected light microscopy of suitable sections of the materialsamples. Such surface defects usually have mean diameters of from about10 μm to about 300 μm.

In the preparation according to the invention of the pigment/carbonblack-containing polymer/polycarbonate moulding compositions, furtherprocess-related measures can be taken which further assist in improvingthe dispersion of the pigment/carbon black in the polymer matrix. Forexample, during the compounding of the pigment/carbon black-containingpolymer/polycarbonate moulding compositions in the melt, water can beadded in amounts of from 0.2 to 10 wt. %, based on the mouldingcomposition, and removed again via a degassing nozzle of the extruder,as described in DE 10 2009 009680 and EP 10001490.1. Likewise,compounding of the pigment/carbon black-containing polymer/polycarbonatemoulding compositions can be carried out on extruders having enlargedgap widths between the screw crest and the housing wall, as described inEP 1016954.7. All these measures bring about improvements in thedispersion of the pigment/carbon black in the polymer/polycarbonatemoulding compositions both on their own and in combination with oneanother.

Component a

There can be used as thermoplastic polymers a in the compositionsaccording to the invention, for example, polyolefins (such aspolyethylene and polypropylene), vinyl (co)polymers such as polyvinylchloride, styrene (co)polymers (e.g. styrene-acrylonitrile copolymers,acrylonitrile-butadiene-styrene copolymers, polyacrylates,polyacrylonitrile), polyvinyl acetate, thermoplastic polyurethanes,polyacetals (such as polyoxymethylene and polyphenylene ether),polyamides, polyimides, polycarbonates, polyesters, polyestercarbonates, polysulfones, polyarylates, polyaryl ethers, polyphenyleneethers, polyarylsulfones, polyaryl sulfides, polyether sulfones,polyphenylene sulfide, polyether ketones, polyamide imides, polyetherimides and polyester imides.

In a preferred embodiment there is used as the thermoplastic polymer ain the compositions according to the invention at least onerepresentative selected from the group of the aromatic polycarbonatesand aromatic polyester carbonates.

Aromatic polycarbonates and/or aromatic polyester carbonates accordingto component a that are suitable according to the invention are known inthe literature or can be prepared by processes known in the literature(for the preparation of aromatic polycarbonates see, for example,Schnell, “Chemistry and Physics of Polycarbonates”, IntersciencePublishers, 1964 and DE-AS 1 495 626, DE-A 2 232 877, BE-A 2 703 376,DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832 396; for the preparation ofaromatic polyester carbonates see e.g. BE-A 3 007 934). The preparationof aromatic polycarbonates is carried out, for example, by reaction ofdiphenols with carbonic acid halides, preferably phosgene, and/or witharomatic dicarboxylic acid dihalides, preferably benzenedicarboxylicacid dihalides, according to the interfacial process, optionally usingchain terminators, for example monophenols, and optionally usingbranching agents having a functionality of three or more than three, forexample triphenols or tetraphenols. Preparation by a melt polymerisationprocess by reaction of diphenols with, for example, diphenyl carbonateis also possible.

Diphenols for the preparation of the aromatic polycarbonates and/oraromatic polyester carbonates are preferably those of formula (I)

whereinA is a single bond, C₁- to C₅-alkylene, C₂- to C₅-alkylidene, C₅- toC₆-cycloalkylidene, —O—, —SO—, —CO—, —S—, —SO₂—, C₆- to C₁₂-arylene, towhich further aromatic rings optionally containing heteroatoms can befused,

or a radical of formula (II) or (III)

B is in each case C₁- to C₁₂-alkyl, preferably methyl, halogen,preferably chlorine and/or bromine,x each independently of the other is 0, 1 or 2,p is 1 or 0, andR⁵ and R⁶ can be chosen individually for each X¹ and each independentlyof the other is hydrogen or C₁- to C₆-alkyl, preferably hydrogen, methylor ethyl,X¹ is carbon andm is an integer from 4 to 7, preferably 4 or 5, with the proviso that onat least one atom X¹, R⁵ and R⁶ are simultaneously alkyl.

Preferred diphenols are hydroquinone, resorcinol, dihydroxydiphenols,bis-(hydroxyphenyl)-C₁-C₅-alkanes,bis-(hydroxyphenyl)-C₅-C₆-cycloalkanes, bis-(hydroxyphenyl) ethers,bis-(hydroxy-phenyl) sulfoxides, bis-(hydroxyphenyl) ketones,bis-(hydroxyphenyl)-sulfones andα,α-bis-(hydroxyphenyl)-diisopropyl-benzenes, and derivatives thereofbrominated and/or chlorinated on the ring.

Particularly preferred diphenols are 4,4′-dihydroxydiphenyl, bisphenolA, 2,4-bis(4-hydroxy-phenyl)-2-methylbutane,1,1-bis-(4-hydroxyphenyl)-cyclohexane,1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenylsulfone and di-and tetra-brominated or chlorinated derivatives thereof, such as, forexample, 2,2-bis(3-chloro-4-hydroxyphenyl)-propane,2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane or2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane.2,2-Bis-(4-hydroxyphenyl)-propane (bisphenol A) is particularlypreferred.

The diphenols can be used on their own or in the form of arbitrarymixtures. The diphenols are known in the literature or are obtainableaccording to processes known in the literature.

Chain terminators suitable for the preparation of thermoplastic aromaticpolycarbonates are, for example, phenol, p-chlorophenol,p-tert-butylphenol or 2,4,6-tribromophenol, but also long-chainedalkylphenols, such as 4-[2-(2,4,4-trimethylpentyl]-phenol,4-(1,3-tetramethylbutyl)-phenol according to DE-A 2 842 005 ormonoalkylphenol or dialkylphenols having a total of from 8 to 20 carbonatoms in the alkyl substituents, such as 3,5-di-tert-butylphenol,p-isooctylphenol, p-tert-octylphenol, p-dodecylphenol and2-(3,5-dimethylheptyl)-phenol and 4-(3,5-dimethylheptyl)-phenol. Theamount of chain terminators to be used is generally from 0.5 mol % to 10mol %, based on the molar sum of the diphenols used in a particularcase.

The thermoplastic aromatic polycarbonates have mean weight-averagemolecular weights (M_(w), measured by GPC (gel permeation chromatographywith polycarbonate standard in dichloromethane) of from 10,000 to200,000 g/mol, preferably from 15,000 to 80,000 g/mol, particularlypreferably from 24,000 to 32,000 g/mol.

The thermoplastic aromatic polycarbonates can be branched in a knownmanner, preferably by the incorporation of from 0.05 to 2.0 mol %, basedon the sum of the diphenols used, of compounds having a functionality ofthree or more than three, for example those having three or morephenolic groups. Preference is given to linear polycarbonates, morepreferably based on bisphenol A.

Both homopolycarbonates and copolycarbonates are suitable. For thepreparation of copolycarbonates of component a according to theinvention it is also possible to use from 1 to 25 wt. %, preferably from2.5 to 25 wt. %, based on the total amount of diphenols to be used, ofpolydiorganosiloxanes having hydroxyaryloxy end groups. These are known(U.S. Pat. No. 3,419,634) and can be prepared according to processesknown in the literature. Polydiorganosiloxane-containingcopolycarbonates are likewise suitable; the preparation ofcopolycarbonates containing polydiorganosiloxanes is described, forexample, in DE-A 3 334 782.

Preferred polycarbonates in addition to the bisphenol Ahomopolycarbonates are the copolycarbonates of bisphenol A with up to 15mol %, based on the molar sums of diphenols, of diphenols other thanthose mentioned as being preferred or particularly preferred, inparticular 2,2-bis(3,5-dibromo-4-hydroxyphenyl)-propane.

Aromatic dicarboxylic acid dihalides for the preparation of aromaticpolyester carbonates are preferably the diacid dichlorides ofisophthalic acid, terephthalic acid, diphenyl ether 4,4′-dicarboxylicacid and naphthalene-2,6-dicarboxylic acid.

Mixtures of the diacid dichlorides of isophthalic acid and terephthalicacid in a ratio of from 1:20 to 20:1 are particularly preferred.

In the preparation of polyester carbonates, a carbonic acid halide,preferably phosgene, is additionally used concomitantly as bifunctionalacid derivative.

Suitable chain terminators for the preparation of the aromatic polyestercarbonates, in addition to the monophenols already mentioned, are alsothe chlorocarbonic acid esters thereof and the acid chlorides ofaromatic monocarboxylic acids, which can optionally be substituted byC₁- to C₂₂-alkyl groups or by halogen atoms, as well as aliphatic C₂- toC₂₂-monocarboxylic acid chlorides.

The amount of chain terminators is in each case from 0.1 to 10 mol %,based in the case of phenolic chain terminators on moles of diphenol andin the case of monocarboxylic acid chloride chain terminators on molesof dicarboxylic acid dichloride.

In the preparation of aromatic polyester carbonates, one or morearomatic hydroxycarboxylic acids can additionally be used.

The aromatic polyester carbonates can be both linear and branched inknown manner (see in this connection DE-A 2 940 024 and DE-A 3 007 934),linear polyester carbonates being preferred.

There can be used as branching agents, for example, carboxylic acidchlorides, such as trimesic acid trichloride, cyanuric acid trichloride,3,3′-,4,4′-benzophenone-tetracarboxylic acid tetrachloride,1,4,5,8-naphthalenetetracarboxylic acid tetrachloride or pyromelliticacid tetrachloride, in amounts of from 0.01 to 1.0 mol % (based ondicarboxylic acid dichlorides used), or phenols having a functionalityof three or more, such as phloroglucinol,4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-hept-2-ene,4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane,1,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,1-tri-(4-hydroxyphenyl)-ethane,tri-(4-hydroxyphenyl)-phenylmethane,2,2-bis[4,4-bis(4-hydroxyphenyl)-cyclohexyl]-propane,2,4-bis(4-hydroxyphenylisopropyl)-phenol,tetra-(4-hydroxyphenyl)-methane,2,6-bis(2-hydroxy-5-methyl-benzyl)-4-methyl-phenol,2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)-propane,tetra-(4-[4-hydroxyphenyl-isopropyl]-phenoxy)-methane,1,4-bis[4,4′-dihydroxytriphenyl)-methyl]-benzene, in amounts of from0.01 to 1.0 mol %, based on diphenols used. Phenolic branching agentscan be placed in a vessel with the diphenols; acid chloride branchingagents can be introduced together with the acid dichlorides.

The content of carbonate structural units in the thermoplastic aromaticpolyester carbonates can vary as desired. The content of carbonategroups is preferably up to 100 mol %, in particular up to 80 mol %,particularly preferably up to 50 mol %, based on the sum of ester groupsand carbonate groups. Both the esters and the carbonates contained inthe aromatic polyester carbonates can be present in the polycondensationproduct in the form of blocks or distributed randomly.

The thermoplastic aromatic polycarbonates and polyester carbonates canbe used on their own or in an arbitrary mixture.

Components a which are particularly preferably used according to theinvention are polycarbonates, with bisphenol A homopolycarbonates beingparticularly preferred.

Component b

There are used as component b in principle any desired inorganic ororganic, natural or synthetically prepared pigments. A pigment isunderstood as being a colour-giving substance which is insoluble in theapplication medium (here the thermoplastic polymer according tocomponent a). Examples of such pigments are titanium dioxide, carbonblack, bismuth pigments, metal oxides, metal hydroxides, metal sulfides,iron cyan blue, ultramarine, cadmium pigments, chromate pigments, azopigments as well as polycyclic pigments.

There are preferably used as component b those pigments which havestrong interparticle binding forces (van der Waals forces), becausethese are particularly difficult to disperse.

Component b is particularly preferably at least one carbon-based pigmentselected from the group consisting of carbon black, graphite, fullerene,graphene, activated charcoal and carbon nanotubes (CNTs).

There are suitable as carbon nanotubes both those having a single-layerwall (single-walled carbon nanotubes=SWCNTs) and those having amulti-layer wall (multi-walled carbon nanotubes=MWCNTs).

Carbon nanotubes (CNTs) are preferably understood as being cylindricalcarbon tubes having a carbon content of >95%, which tubes do not containany amorphous carbon. The carbon nanotubes preferably have an outsidediameter of from 3 to 80 nm, particularly preferably from 5 to 20 nm.The mean value of the outside diameter is preferably from 13 to 16 nm.The length of the cylindrical carbon nanotubes is preferably from 0.1 to20 μm, particularly preferably from 1 to 10 μm. The carbon nanotubespreferably consist of from 2 to 50, particularly preferably from 3 to15, graphitic layers (also referred to as “walls”), which have asmallest inside diameter of from 2 to 6 nm. These carbon nanotubes arealso referred to as “carbon fibrils” or “hollow carbon fibres”, forexample.

The production of the CNTs used according to the invention is generallyknown (see e.g. U.S. Pat. No. 5,643,502 and DE-A 10 2006 017 695); theyare preferably produced by the process disclosed in DE-A 10 2006 017695, particularly preferably by the process disclosed in Example 3 ofDE-A 10 2006 017 695.

In an alternative embodiment, carbon-based pigments according tocomponent b are preferably not used in the form of carbon nanotubes, butcarbon-based pigments with the exception of CNTs, preferably carbonblack, particularly preferably colour carbon black, are employed ascomponent b.

Carbon black is a black pulverulent solid which, depending on thequality and use, consists substantially of carbon. The carbon content ofcarbon black is generally from 80.0 to 99.9 wt. %. In the case of carbonblacks which have not been subjected to oxidative after-treatment, thecarbon content is preferably from 96.0 to 95.5 wt. %. By extraction ofthe carbon black with organic solvents, for example with toluene, tracesof organic impurities on the carbon black can be removed and the carboncontent can thereby be increased to more than 99.9 wt. %. In the case ofcarbon blacks which have undergone oxidative after-treatment, the oxygencontent can be up to 30 wt. %, preferably up to wt. %, in particularfrom 5 to 15 wt. %.

Carbon black consists of mostly spherical primary particles having asize of preferably from 10 to 500 nm. These primary particles have growntogether to form chain-like or branched aggregates. The aggregates aregenerally the smallest unit of the carbon black which can be separatedin a dispersing process. Many of these aggregates in turn combine byintermolecular (van der Waals) forces to form agglomerates. By varyingthe production conditions, both the size of the primary particles andthe aggregation (structure) thereof can purposively be adjusted. Theperson skilled in the art understands structure as being the type ofthree-dimensional arrangement of the primary particles in an aggregate.A “high structure” refers to carbon blacks with highly branched andcrosslinked aggregate structures; in the case of largely linearaggregate structures, that is to say aggregate structures with littlebranching and crosslinking, on the other hand, the term “low structure”is used.

The oil adsorption number measured according to ISO 4656 with dibutylphthalate (DBP) is generally given as a measure of the structure of acarbon black. A high oil absorption number is indicative of a highstructure.

The primary particle size of a carbon black can be determined, forexample, by means of scanning electron microscopy. However, the BETsurface area of the carbon black, determined according to ISO 4652 withnitrogen adsorption, is also used as a measure of the primary particlesize of a carbon black. A high BET surface area is indicative of a smallprimary particle size.

The dispersibility of the agglomerates of a carbon black depends on theprimary particle size and the structure of the aggregates, thedispersibility of the carbon black generally decreasing as the primaryparticle size and the structure decrease.

As a commercial product, industrial carbon black is produced byincomplete combustion or pyrolysis of hydrocarbons. Processes for theproduction of industrial carbon black are known in the literature. Knownprocesses for the production of industrial carbon blacks are inparticular the furnace, gas black, flame black, acetylene black andthermal black processes.

The particle size distribution of the primary particles and the size andstructure of the primary particle aggregates determine the propertiessuch as depth of colour, ground shade and conductivity of the carbonblack. Conductive carbon blacks generally have small primary particlesand highly branched aggregates. Colour carbon blacks are generallycarbon blacks with very small primary particles and are often subjectedto subsequent oxidation after production by one of the above-mentionedprocesses. The oxidic groups thereby attached to the carbon blacksurface are intended to increase the compatibility with the resins intowhich the carbon blacks are to be introduced and dispersed.

Colour carbon blacks are preferably used as component b. In a preferredembodiment they have a mean primary particle size, determined byscanning electron microscopy, of from 10 to 100 nm, more preferably from10 to 50 nm, particularly preferably from 10 to 30 nm, in particularfrom 10 to 20 nm. The particularly finely divided colour carbon blacksare therefore particularly preferred in the process according to theinvention because the depth of colour and UV resistance which can beachieved with a particular amount of carbon black increases as theprimary particle size decreases but, on the other hand, theirdispersibility also decreases, for which reason such very finely dividedcarbon blacks in particular are in need of improvement in respect oftheir dispersibility.

The colour carbon blacks which are preferably used as component b have aBET surface area, determined according to ISO 4652 by nitrogenadsorption, of preferably at least 20 m²/g, more preferably of at least50 m²/g, particularly preferably of at least 100 m²/g, in particular ofat least 150 m²/g.

Colour carbon blacks which are preferably used as component b areadditionally characterised by an oil adsorption number, measuredaccording to ISO 4656 with dibutyl phthalate (DBP), of preferably from10 to 200 ml/100 g, more preferably from 30 to 150 ml/100 g,particularly preferably from 40 to 120 ml/100 g, in particular from 40to 80 ml/100 g. The colour carbon blacks with a low oil adsorptionnumber generally achieve a better depth of colour and are preferred inthat regard but, on the other hand, they are generally more difficult todisperse, for which reason such carbon blacks in particular are in needof improvement in respect of their dispersibility.

The carbon blacks which are used as component b can and are preferablyused in pellet or pearl form. Pearl formation or pelletisation iscarried out by processes known in the literature and serves on the onehand to increase the bulk density and improve the metering (flow)properties but, on the other hand, is also carried out for occupationalhealth reasons. The pellets or pearls are preferably so adjusted interms of their hardness that they withstand transport and feedingprocesses during metering largely undamaged but break up intoagglomerates again completely under the action of high mechanical shearforces as occur, for example, in conventional powder mixing devicesand/or compounding units.

Component c

Demoulding agents which can be used according to the invention arecompounds having softening temperatures of preferably below 120° C.,particularly preferably from 20° C. to 100° C., most particularlypreferably from 40° C. to 80° C., such as, for example, low molecularweight polyolefin oils or waxes, montan waxes, aliphatic or aromaticcarboxylic acid esters based on fatty acids and/or fatty alcohols.Demoulding agents which are preferred according to the invention arealiphatic carboxylic acid esters. These are esters of aliphaticlong-chained carboxylic acids with mono- or di-valent aliphatic and/oraromatic, preferably aliphatic, hydroxy compounds.

Aliphatic carboxylic acid esters which are particularly preferably usedare or contain compounds of the general formula (IV):(R₂—CO—O)_(o)—R₃—(OH)_(p) where o=1 to 4 and p=0 to 3  (IV),wherein R₂ is an aliphatic saturated or unsaturated, linear, cyclic orbranched alkyl radical and R₃ is an alkylene radical of a mono- totetra-hydric aliphatic alcohol of the formula R₃—(OH)_(o+p). In thecompounds of formula (IV), the o radicals R₂ in the same molecule canalso have different structures.

Particularly preferred for R₂ are C₁-C₃₀-, particularly preferablyC₄-C₂₈-, most particularly preferably C₁₂-C₂₄-alkyl radicals.C₁-C₃₀-Alkyl represents, for example, methyl, ethyl, n-propyl,isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl,2-methylbutyl, 3-methylbutyl, neopentyl, 1-ethylpropyl, cyclohexyl,cyclopentyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl,1,2-dimethylpropyl, 1-methylpentyl, 2-methylpropyl, 3-methylpentyl,4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl,2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl,2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl,1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl or1-ethyl-2-methylpropyl, n-heptyl and n-octyl, pinacyl, adamantyl, theisomeric menthyls, n-nonyl, n-decyl, n-dodecyl, n-tridecyl,n-tetradecyl, n-hexadecyl or n-octadecyl.

Particularly preferred for R₃ are C₁-C₃₀-, particularly preferablyC₁-C₁₈-alkylene radicals. Alkylene represents a straight-chained,cyclic, branched or unbranched alkylene radical. C₁-C₁₈-Alkylenerepresents, for example, methylene, ethylene, n-propylene, isopropylene,n-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene,n-nonylene, n-decylene, n-dodecylene, n-tridecylene, n-tetradecylene,n-hexadecylene or n-octadecylene.

In the case of esters of polyhydric alcohols, free, non-esterified OHgroups can also be present. Aliphatic carboxylic acid esters which aresuitable according to the invention are, for example and preferably,glycerol monostearate (GMS), palmityl palmitate and stearyl stearate.Mixtures of different carboxylic acid esters of formula (IV) can also beused. Carboxylic acid esters which are preferably used are additionallymono- or poly-esters of pentaerythritol, glycerol, trimethylolpropane,propanediol, stearyl alcohol, cetyl alcohol or myristyl alcohol withmyristic, palmitic, stearic or montanic acid and mixtures thereof.Pentaerythritol tetrastearate, glycerol monostearate, stearyl stearateand propanediol distearate, or mixtures thereof, are particularlypreferred.

A particularly preferred demoulding agent according to the invention ispentaerythritol tetrastearate and glycerol monostearate, in particularpentaerythritol tetrastearate.

Component d

Thermoplastic polyesters according to component d which can be usedaccording to the invention are polyalkylene terephthalates, which can beprepared by methods known in the literature (see e.g.Kunststoff-Handbuch, Volume VIII, p, 695 ff, Carl-Hanser-Verlag, Munich1973).

In a preferred embodiment, the polyalkylene terephthalates are reactionproducts of aromatic dicarboxylic acids or reactive derivatives thereof,such as dimethyl esters or anhydrides, and aliphatic, cycloaliphatic oraraliphatic diols, as well as mixtures of these reaction products.

Particularly preferred polyalkylene terephthalates contain at least 80wt. %, preferably at least 90 wt. %, based on the dicarboxylic acidcomponent, terephthalic acid radicals and at least 80 wt. %, preferablyat least 90 mol %, based on the diol component, ethylene glycol and/or1,4-butanediol radicals.

Particular preference is given to polyalkylene terephthalates which havebeen prepared solely from terephthalic acid and reactive derivativesthereof (e.g. dialkyl esters thereof) and ethylene glycol and/or1,4-butanediol, and mixtures of these polyalkylene terephthalates.Polyalkylene terephthalates which are particularly preferably usedaccording to the invention are polybutylene terephthalate (PBT) andpolyethylene terephthalate (PET).

Component e

There can be used according to the invention as component e anyelastomers other than component f which have a glass transitiontemperature <10° C., preferably <0° C., particularly preferably <−20° C.

There are preferably used as component e, for example, thermoplasticelastomers such as, for example, olefin-based thermoplastic elastomers(TPO), polyurethane-based thermoplastic elastomers (TPU), andthermoplastic styrene block copolymers (TPS).

Unless expressly described otherwise in the present invention, the glasstransition temperature is determined for all components by means ofdifferential scanning calorimetry (DSC) according to DIN EN 61006 at aheating rate of 10 K/min with determination of the Tg as the mid-pointtemperature (tangent method).

Component f

Rubber-modified vinyl (co)polymers which can be used according to theinvention as component fare one or more graft polymers of

-   f.1 from 5 to 95 wt. %, preferably from 10 to 90 wt. %, particularly    preferably from 30 to 60 wt. %, of at least one vinyl monomer on-   f.2 from 95 to 5 wt. %, preferably from 90 to 10 wt. %, particularly    preferably from 70 to 40 wt. %, of one or more graft bases having    glass transition temperatures <10° C., preferably <0° C.,    particularly preferably <−20° C.

The graft base f.2 generally has a mean particle size (d50 value) offrom 0.05 to 10.00 μm, preferably from 0.10 to 5.00 μm, more preferablyfrom 0.15 to 1.00 μm and particularly preferably from 0.2 to 0.5 μm.

The mean particle size d50 is the diameter above and below which in eachcase 50 wt. % of the particles lie. It can be determined by means ofultracentrifuge measurement (W. Scholtan, H. Lange, Kolloid, Z. und Z.Polymere 250 (1972), 782-1796).

Monomers f.1 are preferably mixtures of

-   f.1.1 from 50 to 99 parts by weight of vinyl aromatic compounds    and/or vinyl aromatic compounds substituted on the ring (such as    styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene) and/or    (meth)acrylic acid (C1-C8)-alkyl esters, such as methyl    methacrylate, ethyl methacrylate, and-   f.1.2 from 1 to 50 parts by weight of vinyl cyanides (unsaturated    nitriles such as acrylonitrile and methacrylonitrile) and/or    (meth)acrylic acid (C1-C8)-alkyl esters, such as methyl    methacrylate, n-butyl acrylate, tert-butyl acrylate, and/or    derivatives (such as anhydrides and imides) of unsaturated    carboxylic acids, for example maleic anhydride.

Preferred monomers f.1.1 are selected from at least one of the monomersstyrene, α-methylstyrene and methyl methacrylate, preferred monomersf.1.2 are selected from at least one of the monomers acrylonitrile,maleic anhydride and methyl methacrylate. Particularly preferredmonomers are f.1.1 styrene and f.1.2 acrylonitrile.

Graft bases f.2 suitable for the graft polymers according to component fare, for example, diene rubbers, EP(D)M rubbers, that is to say thosebased on ethylene/propylene and optionally diene, acrylate,polyurethane, silicone, chloroprene, ethylene/vinyl acetate andacrylate-silicone composite rubbers.

Preferred graft bases f.2 are diene rubbers, for example based onbutadiene and isoprene, or mixtures of diene rubbers or copolymers ofdiene rubbers or mixtures thereof with further copolymerisable monomers(e.g. according to f.1.1 and f.1.2), with the proviso that the glasstransition temperature of component f.2 is below <10° C., preferably <0°C., particularly preferably <−10° C. Pure polybutadiene rubber isparticularly preferred.

The gel content of the graft base f.2 is at least 30 wt. %, preferablyat least 40 wt. %, particularly preferably at least 70 wt. % (measuredin toluene).

The gel content of the graft base f.2 is determined at 25° C. in asuitable solvent (M. Hoffmann, H. Krömer, R. Kuhn, Polymeranalytik I undII, Georg Thieme-Verlag, Stuttgart 1977).

Particularly preferred rubber-modified vinyl (co)polymers according tocomponent f are, for example, ABS polymers (emulsion, mass andsuspension ABS), as are described, for example, in DE-OS 2 035 390(=U.S. Pat. No. 3,644,574) or in DE-OS 2 248 242 (=GB-PS 1 409 275) orin Ullmanns, Enzyklopädie der Technischen Chemie, Vol. 19 (1980), p. 280ff.

The graft copolymers according to component f are prepared by radicalpolymerisation, for example by emulsion, suspension, solution or masspolymerisation, preferably by emulsion or mass polymerisation,particularly preferably by emulsion polymerisation.

Particularly suitable graft rubbers are also ABS polymers which areprepared by the emulsion polymerisation process by redox initiation withan initiator system comprising organic hydroperoxide and ascorbic acidaccording to U.S. Pat. No. 4,937,285.

Because it is known that, in the graft reaction, the graft monomers arenot necessarily grafted onto the graft base completely, rubber-modifiedgraft polymers according to component f are also understood according tothe invention as being those products which are obtained by(co)polymerisation of the graft monomers f.1 in the presence of thegraft base f.2 and which also form during working up.

Acrylate rubbers suitable as the graft base f.2 are preferably polymersof acrylic acid alkyl esters, optionally with up to 40 wt. %, based onf.2, of other polymerisable, ethylenically unsaturated monomers. Thepreferred polymerisable acrylic acid esters include C1- to C8-alkylesters, for example methyl, ethyl, butyl, n-octyl and 2-ethylhexylesters; haloalkyl esters, preferably halo-C1-C8-alkyl esters, such aschloroethyl acrylate, as well as mixtures of these monomers.

For crosslinking, monomers having more than one polymerisable doublebond can be copolymerised. Preferred examples of crosslinking monomersare esters of unsaturated monocarboxylic acids having from 3 to 8 carbonatoms and unsaturated monohydric alcohols having from 3 to 12 carbonatoms or saturated polyols having from 2 to 4 OH groups and from 2 to 20carbon atoms, such as ethylene glycol dimethacrylate, allylmethacrylate; polyunsaturated heterocyclic compounds, such as trivinyland triallyl cyanurate; polyfunctional vinyl compounds, such as di- andtri-vinylbenzenes; but also triallyl phosphate and diallyl phthalate.Preferred crosslinking monomers are allyl methacrylate, ethylene glycoldimethacrylate, diallyl phthalate, and heterocyclic compounds whichcontain at least three ethylenically unsaturated groups. Particularlypreferred crosslinking monomers are the cyclic monomers triallylcyanurate, triallyl isocyanurate, triacryloyl-hexahydro-s-triazine,triallyl benzenes. The amount of crosslinked monomers is preferably from0.02 to 5.00 wt. %, in particular from 0.05 to 2.00 wt. %, based on thegraft base B.2. In the case of cyclic crosslinking monomers having atleast three ethylenically unsaturated groups, it is advantageous tolimit the amount to less than 1 wt. % of the graft base f.2.

Preferred “other” polymerisable, ethylenically unsaturated monomerswhich can optionally be used in addition to the acrylic acid esters forthe preparation of acrylate rubbers suitable as the graft base f.2 are,for example, acrylonitrile, styrene, α-methylstyrene, acrylamides, vinylC1-C6-alkyl ethers, methyl methacrylate, butadiene. Preferred acrylaterubbers as the graft base f.2 are emulsion polymers having a gel contentof at least 60 wt. %.

Further suitable graft bases according to f.2 are silicone rubbershaving graft-active sites, as are described in DE-OS 3 704 657, DE-OS 3704 655, DE-OS 3 631 540 and DE-OS 3 631 539.

Rubber-free vinyl (co)polymers which can be used according to theinvention as component f are, for example and preferably, homo- and/orco-polymers of at least one monomer from the group of the vinyl aromaticcompounds, vinyl cyanides (unsaturated nitriles), (meth)acrylic acid(C1-C8)-alkyl esters, unsaturated carboxylic acids, as well asderivatives (such as anhydrides and imides) of unsaturated carboxylicacids.

Particularly suitable are (co)polymers of from 50 to 99 parts by weight,preferably from 60 to 80 parts by weight, in particular from 70 to 80parts by weight, in each case based on the (co)polymer, of at least onemonomer selected from the group of the vinyl aromatic compounds (suchas, for example, styrene, α-methylstyrene), vinyl aromatic compoundssubstituted on the ring (such as, for example, p-methylstyrene,p-chlorostyrene) and (meth)acrylic acid (C1-C8)-alkyl esters (such as,for example, methyl methacrylate, n-butyl acrylate, tert-butylacrylate), and from 1 to 50 parts by weight, preferably from 20 to 40parts by weight, in particular from 20 to 30 parts by weight, in eachcase based on the (co)polymer, of at least one monomer selected from thegroup of the vinyl cyanides (such as, for example, unsaturated nitrilessuch as acrylonitrile and methacrylonitrile), (meth)acrylic acid(C1-C8)-alkyl esters (such as, for example, methyl methacrylate, n-butylacrylate, tert-butyl acrylate), unsaturated carboxylic acids andderivatives of unsaturated carboxylic acids (for example maleicanhydride and N-phenyl-maleimide). The copolymer of styrene andacrylonitrile is particularly preferred.

Such vinyl (co)polymers are known and can be prepared by radicalpolymerisation, in particular by emulsion, suspension, solution or masspolymerisation.

In an embodiment which is particularly preferred according to theinvention, the vinyl (co)polymers have a weight-average molar mass M_(w)(determined by gel chromatography in dichloromethane with polystyrenecalibration) of from 50,000 to 250,000 g/mol, particularly preferablyfrom 70,000 to 180,000 g/mol.

Component g

Additives according to component g which can be used according to theinvention are, for example, flameproofing agents (for example halogencompounds or phosphorus compounds such as monomeric or oligomericorganic phosphoric acid esters, phosphazenes or phosphonate amines, inparticular bisphenol A diphosphate, resorcinol diphosphate and triphenylphosphate), flameproofing synergists (for example nano-scale metaloxides), smoke-inhibiting additives (for example boric acid or borates),antidripping agents (for example compounds of the substance classes ofthe fluorinated polyolefins, of the silicones as well as aramid fibres),antistatics (for example block copolymers of ethylene oxide andpropylene oxide, other polyethers or polyhydroxy ethers, polyetheramides, polyester amides or sulfonic acid salts), conductivity additivesother than the definition of component b, stabilisers (for exampleUV/light stabilisers, heat stabilisers, antioxidants,transesterification inhibitors, hydrolytic stabilisers), additiveshaving antibacterial action (for example silver or silver salts),additives improving scratch resistance (for example silicone oils orhard fillers such as (hollow) ceramics beads), IR absorbers, opticalbrightening agents, fluorescent additives, fillers and reinforcingsubstances other than the definition of component b (for example talc,optionally ground glass fibres, (hollow) glass or ceramics beads, mica,kaolin, CaCO₃ and glass flakes), colourings, ground thermoplasticpolymers and Brönstedt-acidic compounds as base acceptors, or mixturesof a plurality of the mentioned additives.

The polymer mixtures prepared according to the invention are preferablyused in the production of injection-moulded articles or of extrudates inwhich particular demands are made as regards the homogeneity and freedomfrom defects of the surfaces.

Examples of moulded articles according to the invention are profiles,films, casing parts of any kind, in particular casing parts forcomputers, laptops, mobile telephones, television surrounds; for officeequipment such as monitors, printers, copiers; for sheets, tubes,conduits for electrical installations, windows, doors and profiles forthe construction sector, interior fitting and external applications; inthe field of electrical engineering, for example for switches andsockets. The moulded articles according to the invention can also beused for interior fittings for passenger vehicles, railway vehicles,ships, aircraft, buses and other motor vehicles, as well as forautomotive bodywork parts. Further moulded articles are food and drinkspackaging and structural components which are galvanised or metallisedafter injection moulding.

EXAMPLES Raw Materials Used

a1

Linear polycarbonate based on bisphenol A having a weight-averagemolecular weight M_(w) of 17,000 g/mol (determined by GPC in methylenechloride at 25° C. with polycarbonate calibration).

a2

Linear polycarbonate based on bisphenol A having a weight-averagemolecular weight M_(w) of 25,000 g/mol (determined by GPC in methylenechloride at 25° C. with polycarbonate calibration).

a3

Linear polycarbonate based on bisphenol A having a weight-averagemolecular weight M_(w) of 28,000 g/mol (determined by GPC in methylenechloride at 25° C. with polycarbonate calibration).

a4

Linear polycarbonate based on bisphenol A having a weight-averagemolecular weight M_(w) of 30,000 g/mol (determined by GPC in methylenechloride at 25° C. with polycarbonate calibration).

a5

Linear polycarbonate based on bisphenol A having a weight-averagemolecular weight M_(w) of 36,000 g/mol (determined by GPC in methylenechloride at 25° C. with polycarbonate calibration)

a6

Linear copolycarbonate of bisphenol A and1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane in a mixing ratioof 70 wt. %:30 wt. % having a melt viscosity measured according to ISO11433 at a temperature of 340° C. and a shear rate of 1000 s⁻¹ of 400Pas.

a7

Linear polycarbonate of bisphenol A and1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane in a mixing ratioof 30 wt. %:70 wt. % having a melt viscosity measured according to ISO11433 at a temperature of 340° C. and a shear rate of 1000 s⁻¹ of 320Pas.

a8

Component a2 ground to powder

a9

Linear polycarbonate based on bisphenol A having a weight-averagemolecular weight M_(w) of 32,000 g/mol (determined by GPC in methylenechloride at 25° C. with polycarbonate calibration), ground to powder

b1

Black Pearls 800 (Cabot Corporation, Leuven, Belgium): pearled pigmentcarbon black having a mean primary particle size determined by scanningelectron microscopy of 17 nm, a BET surface area determined according toISO 4652 by nitrogen adsorption of 210 m²/g and an oil adsorption numbermeasured according to ISO 4656 with dibutyl phthalate (DBP) of 65 ml/100g.

b2

Printex 85 (Evonik Degussa GmbH, Frankfurt/Main, Germany): pigmentcarbon black having a mean primary particle size determined by scanningelectron microscopy of 16 nm, a BET surface area determined according toISO 4652 by nitrogen adsorption of 200 m²/g and an oil adsorption numbermeasured according to ISO 4656 with dibutyl phthalate (DBP) of 48 ml/100g.

b3

Chromium rutile pigment

b4

Iron oxide pigment

c1

Pentaerythritol tetrastearate (PETS)

c2

Glycerol monostearate (GMS)

c3

Stearyl stearate

c4

LDPE wax (low-density polyethylene wax)

d1

Linear polyethylene terephthalate having an intrinsic viscosity of 0.665measured in phenol/o-dichlorobenzene (1:1 parts by weight) at 25° C.

d2

Linear polybutylene terephthalate having a melt volume flow rate of 45cm²/10 min at 250° C. and 2.16 kg load

f1

Emulsion ABS granules with an A:B:S weight ratio of 20:24:56

f2

Mass ABS granules with an A:B:S weight ratio of 25:10:65

f3

Graft polymer consisting of 28 wt. % styrene-acrylonitrile copolymerwith a ratio of styrene to acrylonitrile of 71 to 29 parts by weight asshell on 72 wt. % of a particulate graft base as core consisting of 46parts by weight, based on the graft base, of silicone rubber and 54parts by weight, based on the graft base, of butyl acrylate rubber,prepared by the emulsion polymerisation process.

f4

Emulsions ABS graft in powder form with an A:B:S weight ratio of12:58:30

f5

Emulsions ABS graft in powder form with an A:B:S weight ratio of 7:75:18

f6

Polymethyl methacrylate (PMMA)-grafted silicone-butyl acrylate compositerubber graft in powder form, prepared by emulsion polymerisation,consisting of a graft shell of 10 wt. %, based on the graft, ofpolymethyl methacrylate and 90 wt. %, based on the graft, of particulatesilicone-butyl acrylate composite rubber base with a silicone content,based on the silicone-butyl acrylate composite rubber base, of 30 wt. %and a butyl acrylate content, based on the silicone-butyl acrylatecomposite rubber base, of 70 wt. %.

f7

Styrene-acrylonitrile copolymer (SAN) with an A:S weight ratio of 24:76

g1

Bisphenol A-based oligophosphate

q=degree of oligomerisationg2

Polytetrafluoroethylene (PTFE) concentrate consisting of 50 wt. %styrene-acrylonitrile (SAN) copolymer and 50 wt. % PTFE

g3

Stabilisers

g4

Talc with a d₅₀ of 1.2 μm.

g5

Water

A) Carbon Black Masterbatches

The carbon black/demoulding agent masterbatches 1 to 14 listed in table1 under component B were prepared as described below.

A.1) Mixing Units Used

Test Arrangement 1

A type MDK/E 46 co-kneader from Buss was used. FIG. 1 shows thestructure in principle. The mixture components were metered into thefeed hopper 1 of the Buss co-kneader 2. The mixture components werethere taken into the co-kneader 2 by the screw (not shown) located onthe inside and were conveyed axially. In the region of the retainingring 3, accumulation of the mixture components took place, as well asmelting of the demoulding agent, intimate mixing of the mixturecomponents and dispersion of the carbon black. In the region of theretaining ring 4, accumulation of the melt mixture took place, as wellas further mixing of the mixture components and dispersion of the carbonblack. In the regions between the feed hopper 1 and the retaining ring3, the retaining ring 3 and the retaining ring 4 and the retaining ring4 and the single-shaft extruder 5 flange-mounted on the co-kneader 2,the kneading blades were so arranged on the screw shaft that the meltmixture was conveyed axially in the direction of the single-shaftextruder 5. In the single-shaft extruder 5, the melt mixture wasconveyed through the single-shaft screw (not shown) and degassed at thedegassing opening 6. At the end of the single-shaft extruder 5 there isa spray head (not shown) having a nozzle plate with 8 holes, each ofwhich has a diameter of 2.5 mm. The melt strands emerging from thenozzle plate were then granulated by means of a hot-face water-ringgranulating system (not shown) known to the person skilled in the art toform granules having a length of up to 5 mm and were cooled. The wateradhering to the granules was then removed by means of a vibro screen(not shown) and subsequent drying in a fluidised bed dryer (not shown).

Test Arrangement 2

As arrangement 1 but without retaining ring 3 (see FIG. 2), so that theenergy input of the co-kneader in test arrangement 2 is lower ascompared with test arrangement 1.

Test Arrangement 3

As arrangement 1 but with an additional metering hopper 7 downstream ofretaining ring 3 (see FIG. 3), so that the carbon black is added in twoportions in two steps via metering hoppers 1 and 7.

Test Arrangement 4

An Evolum HT32 twin-screw extruder from Clextral with a housing insidediameter of 32 mm, a ratio of screw outside diameter to screw insidediameter of 1.55 and a length-to-diameter ratio of 44 was used. Thetwin-screw extruder has a housing consisting of 11 parts, in which twoco-rotating, intermeshing shafts (not shown) are arranged.

The structure of the extruder used is shown in principle in FIG. 4.

Metering of a portion of the pulverulent carbon black and of thepulverulent demoulding agent was carried out by means of differentialproportioning weighers (not shown) via the feed hopper 8 into the mainintake of the extruder in housing 9 (intake housing).

In the region of housings 9 to 11 there is a feed zone in which themixture constituents are taken into the extruder in the solid state andconveyed further.

In the region of housing 12 there is a plastification zone, whichconsists of various conveying double- and triple-threaded kneadingblocks of different widths and a return element at the end of the zone.

In the region of housings 13 and 14 there is a mixing zone, whichconsists of various mixing, kneading and feed elements.

In housing 15, the remaining portion of the pulverulent carbon black ismetered into the extruder via a lateral feed device.

In the region of housings 16 and 17 there is a further mixing zone whichconsists of various mixing, kneading and feed elements.

In housing part 18 (degassing housing) there is the degassing opening20, which is connected to a suction device (not shown).

In housing 19 (discharge housing) there the pressure build-up zone,which is followed by a spray head (not shown) having a nozzle plate with6 holes, each of which has a diameter of 3.2 mm.

Test Arrangement 5

A type MDK/E 100 co-kneader from Buss was used. The structurecorresponded in principle to the structure of test arrangement 3.

Test Arrangement 6

A shear roller unit was used, as is described, for example, in EP0707037 B1.

A.2) Preparation of Masterbatches B1-B16

Carbon black/demoulding agent masterbatches B1 to B4 were prepared usingthe test arrangements, process parameters and formulations indicated inTable 2.

The specific mechanical energy input (SME) indicated in Table 2 wasdetermined according to equation 1.

$\begin{matrix}{{SME} = \frac{2 \cdot \pi \cdot M \cdot n}{\overset{.}{m} \cdot 60000}} & {{Equation}\mspace{14mu} 1}\end{matrix}$SME: specific mechanical energy input in kWh/kgM: torque in Nmn: speed in l/min{dot over (m)}: throughput in kg/h

Carbon black/demoulding agent masterbatch B5 was prepared using testarrangement 5 from 58% b1 and 42% c1.

Carbon black/demoulding agent masterbatches B6 and B7 were preparedusing test arrangement 6 from 50% b1 and 50% c1 (B6) and 65% b1 and 35%c1 (B7).

Carbon black/demoulding agent masterbatches B8 to B14 were preparedusing the test arrangements, process parameters and formulationsindicated in Table 3. The specific mechanical energy input (SME)indicated in Table 3 was calculated according to equation 1.

The carbon black/polycarbonate masterbatch B15 was supplied by ColorSystem S.p.a. Carbon black/polycarbonate masterbatch consisting of 15wt. % b1 and 85 wt. % of a bisphenol A-based polycarbonate having arelative solution viscosity of 1.28 (measured in methylene chloride at25° C.).

The carbon black/polyethylene masterbatch B16 was supplied by Cabot(trade name: Plasblak PE6130). Carbon black/polyethylene masterbatchcontaining 50 wt. % carbon black.

B) PC Moulding Compositions

B.1) Mixing Units Used

Test Arrangement 7

An Evolum HT32 twin-screw extruder from Clextral having a housing insidediameter of 32 mm, a ratio of screw outside diameter to screw insidediameter of 1.55 and a length-to-diameter ratio of 36 was used. Thetwin-screw extruder has a housing consisting of 9 parts, in which twoco-rotating, intermeshing shafts (not shown) are arranged.

The structure of the extruder used is shown in principle in FIG. 5

Metering of all the components was carried out by means of differentialproportioning weighers (not shown) via the feed hopper 8a into the mainintake of the extruder in housing 9a (intake housing).

In the region of housings 9a to 13a there is a feed zone in which themixture constituents are taken into the extruder in the solid state andconveyed further.

In the region of housings 14a and 16a there is a plastification zone,which consists of various conveying double- and triple-threaded kneadingblocks of different widths and a return element at the end of the zone.

In the region of housings 16a and 18a there is a mixing zone whichconsists of various mixing and feed elements.

In housing part 18a (degassing housing) there is the degassing opening20a, which is connected to a suction device (not shown).

In housing 19a (discharge housing) there is the pressure build-up zone,which is followed by a spray head (not shown) having a nozzle plate with6 holes, each of which has a diameter of 3.2 mm.

Test Arrangement 8

As test arrangement 7 but with an injection valve 22 arranged at the endof housing part 21, via which the liquid additive 1 is metered informulations 20 and 21 (FIG. 6).

Test Arrangement 9

A ZSK 25 WLE twin-screw extruder from Coperion Werner & Pfleidererhaving a housing inside diameter of 25.2 mm, a ratio of screw outsidediameter to screw inside diameter of 1.50 and a length-to-diameter ratioof 48 was used. The twin-screw extruder has a housing consisting of 13parts, in which two co-rotating, intermeshing shafts (not shown) arearranged. The structure of the extruder used is shown in principle inFIG. 7. Metering of all the components was carried out by means ofdifferential proportioning weighers (not shown) via the feed hopper 8cinto the main intake of the extruder in housing 9c (intake housing). Inthe region of housings 9c to 12c there is a feed zone in which themixture constituents are taken into the extruder in the solid state andconveyed further. In the region of housings 13c and 23 (intermediateplate) there is a plastification zone, which consists of variousconveying double- and triple-threaded kneading blocks of differentwidths and a return element at the end of the zone. In the region ofhousings 14c to 17c there are two mixing zones, which consist of variousmixing and feed elements. In housing part 18c there is the degassingopening 20c, which is connected to a suction device (not shown). Inhousing 19c (discharge housing) there is the pressure build-up zone,which is followed by a spray head (not shown) having a nozzle plate with2 holes, each of which has a diameter of 4.5 mm.

Test Arrangement 10

A ZSK 133Sc twin-screw extruder from Coperion Werner & Pfleiderer havinga housing inside diameter of 134.4 mm, a ratio of screw outside diameterto screw inside diameter of 1.55 and a length-to-diameter ratio of 31.5was used. The twin-screw extruder has a housing consisting of 10 parts,in which two co-rotating, intermeshing shafts (not shown) are arranged.The structure of the extruder used is shown in principle in FIG. 8.Metering of all the components was carried out by means of differentialproportioning weighers (not shown) via the feed hopper 8d into the mainintake of the extruder in housing 9d (intake housing). In the region ofhousings 9d to 11d there is a feed zone in which the mixtureconstituents are taken into the extruder in the solid state and conveyedfurther. In the region of housings 12d, 23a and 13d there is aplastification zone, which consists of various conveying double- andtriple-threaded kneading blocks of different widths and a return elementat the end of the zone. In the region of housings 14d, 24a and 18d thereis a mixing zone which consists of various mixing and feed elements. Inhousing part 18d (degassing housing) there is the degassing opening 20d,which is connected to a suction device (not shown). In housing 19d(discharge housing) there is the pressure build-up zone, which isfollowed by a spray head (not shown) having a nozzle plate with 60holes, each of which has a diameter of 4.5 mm.

Test Arrangement 11

A ZSK 92Mc twin-screw extruder from Coperion Werner & Pfleiderer havinga housing inside diameter of 92.8 mm, a ratio of screw outside diameterto screw inside diameter of 1.55 and a length-to-diameter ratio of 40was used. The twin-screw extruder has a housing consisting of 10 parts,in which two co-rotating, intermeshing shafts (not shown) are arranged.The structure of the extruder used is shown in principle in FIG. 9.Metering of all the components was carried out by means of differentialproportioning weighers (not shown) via the feed hopper 8e into the mainintake of the extruder in housing 9e (intake housing). In the region ofhousings 9e to 13e there is a feed zone in which the mixtureconstituents are taken into the extruder in the solid state and conveyedfurther. In the region of housings 13e and 14e there is a plastificationzone, which consists of various conveying double- and triple-threadedkneading blocks of different widths and a return element at the end ofthe zone. In housing part 18e (degassing housing) there is the degassingopening 20e, which is connected to a suction device (not shown). Inhousing part 21a there is an injection valve 22a, via whichPETSLoxiolPS613,5Spezial is added in liquid form. In the region ofhousings 21a and 26 there is a mixing zone which consists of variousmixing and feed elements. In housing 19e (discharge housing) there isthe pressure build-up zone, which is followed by a spray head (notshown) having a nozzle plate with 60 holes, each of which has a diameterof 4.5 mm.

B.2) Preparation of the PC Moulding Compositions

The process parameters used in the examples for the preparation of PCmoulding compositions are shown in Table 4. The specific mechanicalenergy input (SME) indicated in Table 4 was determined according toequation 1.

The PC moulding composition granules prepared in the examples wereprocessed by an injection moulding process to sheets with a glossysurface having a size of 150 mm×105 mm×3.2 mm and to test specimenshaving a size of 80 mm×10 mm×4 mm for the Izod notched impact testaccording to ISO 180/1A.

The sheets with a glossy surface were produced on a type FM160 injectionmoulding machine from Klöcknrer. This injection moulding machine has acylinder diameter of 45 mm. To that end, the PC moulding compositiongranules were predried at 110° C. within a period of 4 hours. Processingby injection moulding was carried out under the conditionscharacteristic for polycarbonates or polycarbonate/ABS blends orpolycarbonate/PET blends. An injection moulding tool with a gloss finish(ISO N1) was used for the production of the sheets.

The number of surface defects on the sheets with a glossy surface wasmeasured as described hereinbefore. 3 plates were measured in each case,and the arithmetic mean was determined from the results.

The Izod notched impact strength of the compound prepared was determinedaccording to ISO 180/1A on the test specimens for the notched impacttest. To that end, in each case 10 test specimens were tested, and thearithmetic mean was determined from these results.

Example 1 Comparison

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 1 (Table 1) using testarrangement 7. Carbon black powder according to Table 1 was added as thecarbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and g(additives) and also a9 given in Table 1 in the mentioned amounts,Mixing of the premix was carried out in a container mixer from Mixaco(type CM30 with Z tool) for 4.5 minutes at a speed of 300 l/min and adegree of filling of the mixer of 80%.

The premix and the remaining mixture constituents listed in Table 1where then metered separately from one another, in each case by means ofa differential proportioning weigher (not shown), via the feed hopper 8ainto the main intake into housing 9a of the extruder.

In the plastification zone and the mixing zone in the region of housings14a, 16a and 18a, the meltable mixture constituents were melted, all themixture constituents were dispersed and the melt mixture washomogenised, the melt being degassed in the penultimate housing part18a.

The melt strands emerging from the nozzle plate were cooled in a waterbath and then granulated by means of a strand granulator.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, andthe measured notched impact strength according to ISO 180/1A are listedin Table 4 under Example 1.

Example 2 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm⁻¹/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 4 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), f (elastomer) and g (additives)given in Table 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, andthe measured notched impact strength according to ISO 180/1A are listedin Table 4 under Example 2.

A comparison of Example 2 according to the invention with ComparisonExample 1 shows that, when the carbon black/demoulding agent masterbatchis used, the number of surface defects is markedly smaller and thenotched impact strength at 23° C. and at 0° C. is markedly higher thanwhen the carbon black powder is used. Both these findings indicatebetter dispersion of the carbon black when the carbon black/demouldingagent masterbatch is used, even though the specific mechanical energyinput (SME) has remained almost the same.

Example 3 Comparison

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 18 cm³/O-min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 18 (see Table 1) usingtest arrangement 7. Carbon black powder according to Table 1 was addedas the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and g(additives) and also f4 given in Table 1 in the mentioned amounts.Preparation of the premix and compounding of the moulding compositionwere carried out as described in Example 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 3.

Example 4 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 18 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 19 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component) and g (additives) and also f4given in Table 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 4.

A comparison of Example 4 according to the invention with ComparisonExample 3 shows that, when the carbon black/demoulding agent masterbatchis used, the number of surface defects is markedly smaller than when thecarbon black powder is used. Both these findings indicate betterdispersion of the carbon black when the carbon black/demoulding agentmasterbatch is used, even though the specific mechanical energy input(SME) has remained the same. A comparison of Examples 1 to 4 shows that,in the case of elastomer-containing polycarbonate blends with markedlydifferent melt volume flow rates too, the number of surface defects whenthe carbon black/demoulding agent masterbatch is used is markedlysmaller than when the carbon black powder is used.

Example 5 Comparison

A flame-protected elastomer-containing polycarbonate blend was preparedaccording to formulation 20 (see Table 1) using test arrangement 8.Carbon black powder according to Table 1 was added as the carbon blackcomponent.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent), g2, g3 andalso f4 given in Table 1 in the mentioned amounts. Mixing of the premixwas carried out in a container mixer from Mixaco (type CM30 with Z tool)for 4.5 minutes at a speed of 300 l/min degree of filling of the mixerof 80%.

The premix and the remaining mixture constituents listed in Table 1 werethen metered separately from one another, in each case by means of adifferential proportioning weigher (not shown), via the feed hopper 8binto the main intake into housing 9b of the extruder.

In the plastification zone and the mixing zone in the region of housings12b and 13b, the meltable mixture constituents were melted, the mixtureconstituents metered into the main intake were dispersed and the meltmixture was homogenised. The melt was then degassed in housing part 18b.In housing part 21, liquid g1 (flameproofing agent) was added via aninjection valve 22 and intimately mixed with the melt in the subsequentmixing zone in housing parts 14b and 19b.

The melt strands emerging from the nozzle plate were cooled in a waterbath and then granulated by means of a strand granulator.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, andthe measured notched impact strength according to ISO 180/1A are listedin Table 4 under Example 5.

Example 6 According to the Invention

A flame-protected elastomer-containing polycarbonate blend was preparedaccording to formulation 21 (see Table 1) using test arrangement 8.Carbon black/demoulding agent masterbatch granules according to Table 1,which were prepared as described under A.2, were added as the carbonblack component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), g2, g3 and also f4 given in Table1 in the mentioned amounts. Preparation of the premix and compounding ofthe moulding composition were carried out as described in Example 5.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, andthe measured notched impact strength according to ISO 180/1A are listedin Table 4 under Example 6.

A comparison of Example 6 according to the invention with ComparisonExample 5 shows that, when the carbon black/demoulding agent masterbatchis used, the number of surface defects is markedly smaller and thenotched impact strength at 23° C. is higher than when the carbon blackpowder is used. Both these findings indicate better dispersion of thecarbon black when the carbon black/demoulding agent masterbatch is used,even though the specific mechanical energy input (SME) has remainedalmost the same. A comparison of Examples 5 and 6 with Examples 1 to 4shows that, even when a liquid flameproofing agent is added to anelastomer-containing polycarbonate blend, the number of surface defectsis markedly smaller when the carbon black/demoulding agent masterbatchis used than when the carbon black powder is used.

Example 7 Comparison

A polycarbonate compound having a melt volume flow rate (MVR) of 9.5cm³/10 min (measured according to ISO 1133 at 300° C. and 1.2 kg) wasprepared according to formulation 22 (see Table 1) using testarrangement 7. Carbon black powder according to Table 1 was added as thecarbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and also a9given in Table 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 7.

Example 8 According to the Invention

A polycarbonate compound having a melt volume flow rate (MVR) of 9.5cm³/10 min (measured according to ISO 1133 at 300° C. and 1.2 kg) wasprepared according to formulation 23 (see Table 1) using testarrangement 7. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and also a9given in Table 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 8.

A comparison of Example 8 according to the invention with ComparisonExample 7 shows that, when the carbon black/demoulding agent masterbatchis used, the number of surface defects is smaller than when the carbonblack powder is used. Both these findings indicate better dispersion ofthe carbon black when the carbon black/demoulding agent masterbatch isused, even though the specific mechanical energy input (SME) hasremained almost the same.

Example 9 Comparison

A polycarbonate compound having a melt volume flow rate (MVR) of 5cm³/10 min (measured according to ISO 1133 at 300° C. and 1.2 kg) wasprepared according to formulation 24 (see Table 1) using testarrangement 7. Carbon black powder according to Table 1 was added as thecarbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and also a9given in Table 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 9.

Example 10 According to the Invention

A polycarbonate compound having a melt volume flow rate (MVR) of 5cm³/10 min (measured according to ISO 1133 at 300° C. and 1.2 kg) wasprepared according to formulation 25 (see Table 1) using testarrangement 7. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and also a9given in Table 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 10.

A comparison of Example 10 according to the invention with ComparisonExample 9 shows that, when the carbon black/demoulding agent masterbatchis used, the number of surface defects is smaller than when the carbonblack powder is used. Both these findings indicate better dispersion ofthe carbon black when the carbon black/demoulding agent masterbatch isused, even though the specific mechanical energy input (SME) hasremained the same.

Example 11 Comparison

A high-temperature-resistant polycarbonate compound (Vicat softeningtemperature 203° C. measured according to ISO 306 at 50 N; 120° C./h)having a melt volume flow rate (MVR) of 8 cm³/10 min (measured accordingto ISO 1133 at 330° C. and 2.16 kg) was prepared according toformulation 28 (see Table 1) using test arrangement 7. Carbon blackpowder according to Table 1 was added as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and also a9given in Table 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 11.

Example 12 According to the Invention

A high-temperature-resistant polycarbonate compound (Vicat softeningtemperature 203° C. measured according to ISO 306 at 50 N; 120° C./h)having a melt volume flow rate (MVR) of 8 cm³/10 min (measured accordingto ISO 1133 at 300° C. and 1.2 kg) was prepared according to formulation29 (see Table 1) using test arrangement 7. Carbon black/demoulding agentmasterbatch granules according to Table 1, which were prepared asdescribed under A.2, were added as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and also a9given in Table 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 12.

A comparison of Example 12 according to the invention with ComparisonExample 11 shows that, when the carbon black/demoulding agentmasterbatch is used, the number of surface defects is markedly smallerthan when the carbon black powder is used. Both these findings indicatebetter dispersion of the carbon black when the carbon black/demouldingagent masterbatch is used, even though the specific mechanical energyinput (SME) has remained the same.

Example 13 Comparison

A high-temperature-resistant polycarbonate compound (Vicat softeningtemperature 184° C. measured according to ISO 306 at 50 N; 120° C./h)having a melt volume flow rate (MVR) of 10 cm³/10 min (measuredaccording to ISO 1133 at 330° C. and 2.16 kg) was prepared according toformulation 30 (see Table 1) using test arrangement 7. Carbon blackpowder according to Table 1 was added as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component) and a9 given in Table 1 in thementioned amounts. Preparation of the premix and compounding of themoulding composition were carried out as described in Example 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 13.

Example 14 According to the Invention

A high-temperature-resistant polycarbonate compound (Vicat softeningtemperature 184° C. measured according to ISO 306 at 50 N; 120° C./h)having a melt volume flow rate (MVR) of cm³/10 min (measured accordingto ISO 1133 at 300° C. and 1.2 kg) was prepared according to formulation31 (see Table 1) using test arrangement 7. Carbon black/demoulding agentmasterbatch granules according to Table 1, which were prepared asdescribed under A.2, were added as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component) and a9 given in Table 1 in thementioned amounts. Preparation of the premix and compounding of themoulding composition were carried out as described in Example 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 14.

A comparison of Example 14 according to the invention with ComparisonExample 13 shows that, when the carbon black/demoulding agentmasterbatch is used, the number of surface defects is markedly smallerthan when the carbon black powder is used. Both these findings indicatebetter dispersion of the carbon black when the carbon black/demouldingagent masterbatch is used, even though the specific mechanical energyinput (SME) has remained almost the same.

A comparison of Examples 7 to 14 shows that, in the case ofpolycarbonate compounds with markedly different melt volume flow ratesand Vicat softening temperatures too, the number of surface defects ismarkedly smaller when the carbon black/demoulding agent masterbatch isused than when the carbon black powder is used.

A comparison of Examples 7 to 14 with Examples 1 to 4 shows that, evenin the case of pure polycarbonate compounds without the addition ofelastomer-containing components, the number of surface defects ismarkedly smaller when the carbon black/demoulding agent masterbatch isused than when the carbon black powder is used.

Example 15 Comparison

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 17 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 35 (Table 1) using testarrangement 9. Carbon black powder according to Table 1 was added as thecarbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent), g(additives) and f6 given in Table 1 in the mentioned amounts. Mixing ofthe premix was carried out in a container mixer from Mixaco (type CM30with Z tool) for 4.5 minutes at a speed of 300 l/min and a degree offilling of the mixer of 80%.

The premix and the remaining mixture constituents listed in Table 1 werethen metered separately from one another, in each case by means of adifferential proportioning weigher (not shown), via the feed hopper 8cinto the main intake into housing 9c of the extruder.

In the plastification zone in the region of housings 12c and 13c, themeltable mixture constituents were melted and all the mixtureconstituents were dispersed. In the mixing zone in the region ofhousings 24, 16c, 25 and 17c, the melt mixture was intimately mixed andhomogenised. The melt was degassed in the penultimate housing part 18c.

The melt strands emerging from the nozzle plate were cooled in a waterbath and then granulated by means of a strand granulator.

The process parameters of the extruder are listed in Table 4 underExample 15. The notched impact strength at different ambienttemperatures, measured according to ISO 180/1A, is shown in diagramsFIG. 11 for an injection moulding material temperature of 260° C. andFIG. 12 for an injection moulding material temperature of 300° C. Eachmeasuring point in the diagrams represents the mean value of 10measurements. The number pairs additionally given at the measuringpoints indicate the number of ductile fractured or brittle fracturedtest specimens. “10/0” means, for example, that all 10 test specimenstested are ductile fractured.

Example 16 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 17 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 36 (see Table 1) usingtest arrangement 9. Carbon black/demoulding agent masterbatch granulesaccording to Table 1 which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), g (additives) and f6 given inTable 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 15.

The process parameters of the extruder are listed in Table 4 underExample 16. The notched impact strength at different ambienttemperatures, measured according to ISO 180/1A, is shown in diagramsFIG. 11 for an injection moulding material temperature of 260° C. andFIG. 12 for an injection moulding material temperature of 300° C. Eachmeasuring point in the diagrams represents the mean value of 10measurements. The number pairs additionally given at the measuringpoints indicate the number of ductile fractured or brittle fracturedtest specimens. “10/0” means, for example, that all 10 test specimenstested are ductile fractured.

A comparison of Example 16 according to the invention with ComparisonExample 15 shows that, when the carbon black/demoulding agentmasterbatch is used, the notched impact strength is markedly higher andthe transition from ductile to brittle fracture behaviour occurs atlower temperatures than when the carbon black powder is used. Thisindicates better dispersion of the carbon black when the carbonblack/demoulding agent masterbatch is used, even though the specificmechanical energy input (SME) has remained almost the same.

Example 17 Comparison

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 17 (see Table 1) usingtest arrangement 7. B16 (carbon black/polyethylene masterbatch PlasblakPE6130 (50% carbon black) from Cabot) according to Table 1 was added asthe carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent), g(additives) and f3 given in Table 1 in the mentioned amounts.Preparation of the premix and compounding of the moulding compositionwere carried out as described in Example 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 17.

Example 18 Comparison

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 16 (see Table 1) usingtest arrangement 7. The carbon black/polycarbonate masterbatch B15 (PCBlack 91024 (15% carbon black) from Color Systems) according to Table 1was added as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and g(additives) and also a9 given in Table 1 in the mentioned amounts.Preparation of the premix and compounding of the moulding compositionwere carried out as described in Example 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 18.

Example 19 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 4 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), g (additives) and f3 given inTable 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number; measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 19.

A comparison of Example 19 according to the invention with ComparisonExamples 17 and 18 shows that, when the carbon black/demoulding agentmasterbatch is used, the number of surface defects is markedly smallerthan when masterbatches based on polyethylene (B16) or polycarbonate(B15) are used. Both these findings indicate better dispersion of thecarbon black when the carbon black/demoulding agent masterbatch is used,even though the specific mechanical energy input (SME) has remainedalmost the same.

Example 20 Comparison

An elastomer- and polyester-containing polycarbonate blend having a meltvolume flow rate (MVR) of 12 cm³/10 min (measured according to ISO 1133at 260° C. and 5 kg) was prepared according to formulation 32 (Table 1)using test arrangement 10. Carbon black powder according to Table 1 wasadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and g(additives) and also a8 given in Table 1 in the mentioned amounts.Mixing of the premix was carried out in a container mixer from Mixaco(type CM1000 with MB tool) for 4.5 minutes at a speed of 425 l/min and adegree of filling of the mixer of 80%.

The premix and the remaining mixture constituents listed in Table 1 werethen metered separately from one another, in each case by means of adifferential proportioning weigher (not shown), via the feed hopper 8dinto the main intake into housing 9d of the extruder.

In the plastification zone in the region of housings 12d, 23a and 13d,the meltable mixture constituents were melted and all the mixtureconstituents were dispersed. In the mixing zone in the region ofhousings 14d, 24a and 18d, the mixture constituents were intimatelymixed and the melt mixture was homogenised. The melt mixture wasdegassed in the penultimate housing part 8d.

The melt strands emerging from the nozzle plate were cooled in a waterbath and then granulated by means of a strand granulator.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 20.

Example 21 Comparison

An elastomer- and polyester-containing polycarbonate blend having a meltvolume flow rate (MVR) of 12 cm³/10 min (measured according to ISO 1133at 260° C. and 5 kg) was prepared according to formulation 33 (Table 1)using test arrangement 10. B86 (carbon black/polyethylene masterbatchPlasblak PE6130 (50% carbon black) from Cabot) according to Table 1 wasadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and g(additives) and also a8 given in Table 1 in the mentioned amounts.Preparation of the premix and compounding of the moulding compositionwere carried out as described in Example 20.

The process parameters of the extruder as well as the number, measuredas described above, of surface defects, based on one square centimeter,are listed in Table 4 under Example 21.

Example 22 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 12 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 34 (see Table 1) usingtest arrangement 10. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and g(additives) and also a8 given in Table 1 in the mentioned amounts.Preparation of the premix and compounding of the moulding compositionwere carried out as described in Example 20.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 22.

A comparison of Example 22 according to the invention with ComparisonExamples 20 and 21 shows that, for elastomer- and polyester-containingpolycarbonate blends too, the number of surface defects is markedlysmaller when the carbon black/demoulding agent masterbatch is used thanwhen carbon black powder and a carbon black/polyethylene masterbatchaccording to the prior art are used. Both these findings indicate betterdispersion of the carbon black when the carbon black/demoulding agentmasterbatch is used, even though the specific mechanical energy input(SME) has remained almost the same.

At the same time it is shown that, even with an extruder having a largerscrew outside diameter (133 mm), the number of surface defects ismarkedly smaller when the carbon black/demoulding agent masterbatch isused than when carbon black powder or carbon black masterbatch accordingto the prior art is used.

Example 23 Comparison

A polycarbonate compound having a melt volume flow rate (MVR) of 19cm³/10 min (measured according to ISO 1133 at 300° C. and 1.2 kg) wasprepared according to formulation 26 (see Table 1) using testarrangement 11. Carbon black powder according to Table 1 was added asthe carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and g(additives) and also a8 given in Table 1 in the mentioned amounts.Mixing of the premix was carried out in a container mixer from Mixaco(type CM1000 with MB tool). Components b, g and a8 were first introducedinto the mixing container and mixed for 2 minutes at a speed of 250l/min and a degree of filling of the mixer of 80%. Component c was thenadded to the premixed components in the mixing container and mixed for1.5 minutes at a speed of 350 l/min.

The premix and the remaining mixture constituents listed in Table 1 werethen metered separately from one another, in each case by means of adifferential proportioning weigher (not shown), via the feed hopper 8einto the main intake into housing 9e of the extruder.

In the plastification zone and the mixing zone in the region of housings13e and 14e, the meltable mixture constituents were melted and all themixture constituents were dispersed. In housing 18e, the melt wasdegassed. In housing 21a, liquid g1 (flameproofing agent) was injectedinto the melt via an injection nozzle 22a and intimately mixed with themelt in the subsequent mixing zone in the region of housings 21a, 26 and19e, and the melt mixture was homogenised.

The melt strands emerging from the nozzle plate were cooled in a waterbath and then granulated by means of a strand granulator.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 23.

Example 24 According to the Invention

A polycarbonate compound having a melt volume flow rate (MVR) of 19cm³/10 min (measured according to ISO 1133 at 30° C. and 1.2 kg) wasprepared according to formulation 27 (see Table 1) using testarrangement 11. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), c (demoulding agent) and also a8given in Table 1 in the mentioned amounts. Mixing of the premix wascarried out in a container mixer from Mixaco (type CM1000 with MB tool).Components b, g and a8 were first introduced into the mixing containerand mixed for 2 minutes at a speed of 250 l/min and a degree of fillingof the mixer of 80%. Component c was then added to the premixedcomponents in the mixing container and mixed for 1.5 minutes at a speedof 350 l/min.

Compounding of the moulding composition was carried out as described inExample 23.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 24.

A comparison of Example 24 according to the invention with ComparisonExample 23 shows that, when the carbon black/demoulding agentmasterbatch is used, the number of surface defects is markedly smallerthan when the carbon black powder is used. Both these findings indicatebetter dispersion of the carbon black when the carbon black/demouldingagent masterbatch is used, even though the specific mechanical energyinput (SME) was higher in Example 23 than in Example 24.

At the same time it is shown that, for a polycarbonate compound too, inan extruder having a larger screw outside diameter (92 mm), the numberof surface defects is markedly smaller when the carbon black/demouldingagent masterbatch is used than when carbon black powder is used.

Example 25 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 10 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulescontaining 40 wt. % carbon black according to Table 1, which wereprepared as described under A.2, were added as the carbon blackcomponent.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), g (additives) and f3 given inTable 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 25.

Example 26 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 12 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulescontaining 45 wt. % carbon black according to Table 1, which wereprepared as described under A.2, were added as the carbon blackcomponent.

The procedure in the preparation of the polycarbonate blend correspondedto that of Example 25.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 26.

Example 27

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 9 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulescontaining 50 wt. % carbon black according to Table 1, which wereprepared as described under A.2, were added as the carbon blackcomponent.

The procedure in the preparation of the polycarbonate blend correspondedto that of Example 25.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 27.

Example 28 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 6 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulescontaining 58 wt. % carbon black according to Table 1, which wereprepared as described under A.2, were added as the carbon blackcomponent.

The procedure in the preparation of the polycarbonate blend correspondedto that of Example 25.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 28.

Example 29 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 11 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulescontaining 60 wt. % carbon black according to Table 1, which wereprepared as described under A.2, were added as the carbon blackcomponent.

The procedure in the preparation of the polycarbonate blend correspondedto that of Example 25.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 29.

Example 30 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 8 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulescontaining 65 wt. % carbon black according to Table 1, which wereprepared as described under A.2, were added as the carbon blackcomponent.

The procedure in the preparation of the polycarbonate blend correspondedto that of Example 25.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 30.

A comparison of Examples 25 to 30 according to the invention withComparison Example 1 shows that, even when carbon black/demoulding agentmasterbatches having carbon black contents varying from 40 wt. % to 65wt. % are used, the number of surface defects is markedly lower thanwhen carbon black powder is used. With a carbon black content of 65 wt.% in the masterbatch (Example 30), however, the number of surfacedefects is higher than with 40 wt. % to 60 wt. %, so that 65 wt. %represents the upper carbon black concentration for good dispersion.

In tests with carbon black concentrations less than 40 wt. %, it was notpossible to form a strand because the carbon black-demoulding agentcomposition had too low a viscosity and was tacky. In the tests,therefore, a carbon black concentration of 40 wt. % represented thelower carbon black concentration which could still be processed withoutproblems.

Example 31 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 7 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), g (additives) and f3 given inTable 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 31.

A comparison of Examples 2, 27 and 31 according to the invention withComparison Example 1 shows that, when carbon black/demoulding agentmasterbatches produced either using a co-kneader or using a twin-screwextruder or using shear rollers are used, the number of surface defectsis markedly smaller than when carbon black powder is used.

Example 32 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 13 (see Table 1) usingtest arrangement 7. For the preparation of the compound, a premix wasfirst prepared from components b (carbon black component), g (additives)and f3 given in Table 1 in the mentioned amounts. Preparation of thepremix and compounding of the moulding composition were carried out asdescribed in Example 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 32.

Example 33 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 14 (see Table 1) usingtest arrangement 7. The procedure in the preparation of thepolycarbonate blend corresponded to that of Example 32.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 33.

Example 34 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 15 (see Table 1) usingtest arrangement 7. The procedure in the preparation of thepolycarbonate blend corresponded to that of Example 32.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, arelisted in Table 4 under Example 34.

A comparison of Examples 27, 32, 33 and 34 according to the inventionwith Comparison Example 1 shows that, with c1 or c3 or c4 in the carbonblack/demoulding agent masterbatch, when the carbon black/demouldingagent masterbatch so prepared is used, the number of surface defects ismarkedly smaller than with carbon black powder. Although with c2 in thecarbon black/demoulding agent masterbatch, the number of surface defectsis larger when the carbon black/demoulding agent masterbatch so preparedis used than with c1, c3 or c4, it is still markedly smaller than withcarbon black powder.

Example 35 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 5 (see Table 1) usingtest arrangement 7. For the preparation of the compound, a premix wasfirst prepared from components b (carbon black component), g (additives)and f3 given in Table 1 in the mentioned amounts. Preparation of thepremix and compounding of the moulding composition were carried out asdescribed in Example 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, andthe measured notched impact strength according to ISO 180/1A are listedin Table 4 under Example 35.

A comparison of Examples 2 and 35 according to the invention withComparison Example 1 shows that, with both b2 and b1 as carbon black inthe carbon black/demoulding agent masterbatch, when the carbonblack/demoulding agent masterbatch so prepared is used, the number ofsurface defects is markedly smaller and the notched impact strength at23° C. and at 0° C. is markedly higher than with carbon black powder.

Example 36 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 3 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), g (additives) and f3 given inTable 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, andthe measured notched impact strength according to ISO 180/1A are listedin Table 4 under Example 36.

Example 37 According to the Invention

An elastomer-containing polycarbonate blend having a melt volume flowrate (MVR) of 27 cm³/10 min (measured according to ISO 1133 at 260° C.and 5 kg) was prepared according to formulation 2 (see Table 1) usingtest arrangement 7. Carbon black/demoulding agent masterbatch granulesaccording to Table 1, which were prepared as described under A.2, wereadded as the carbon black component.

For the preparation of the compound, a premix was first prepared fromcomponents b (carbon black component), g (additives) and f3 given inTable 1 in the mentioned amounts. Preparation of the premix andcompounding of the moulding composition were carried out as described inExample 1.

The process parameters of the extruder and the number, measured asdescribed above, of surface defects, based on one square centimeter, andthe measured notched impact strength according to ISO 180/1A are listedin Table 4 under Example 37.

A comparison of Examples 2, 36 and 37 according to the invention withComparison Example 1 shows that, when the carbon black/demoulding agentmasterbatches prepared in a co-kneader with different process parametersand test arrangements are used, the number of surface defects ismarkedly smaller and the notched impact strength at 23° C. and at 0° C.is markedly higher than when the carbon black powder is used.

TABLE 1 (all amounts in wt. %) 95 1 2 3 4 5 6 7 8 all amounts in wt %Comp. Invention Invention Invention Invention Invention InventionInvention a a1 14.14 a2 42.1 73.3 73.3 73.3 73.3 73.34 73.3 73.3 a3 a4a5 a6 a7 a8 a9 16.9 B B1 1.49 B2 1.49 B3 1.49 B4 1.49 B5 1.29 B6 1.49 B71.15 B8 B9 B10 B11 B12 B13 B14 B15 B16 b1 0.75 b3 b4 c c1 0.73 0.16 0.34d d1 d2 f f1 f2 f3 6.89 6.8 6.8 6.8 6.8 6.8 6.8 6.8 f4 f5 f6 f7 17.617.52 17.52 17.52 17.52 17.52 17.52 17.52 g g1 g2 g3 0.89 0.89 0.89 0.890.89 0.89 0.89 0.89 g4 g5 Formulation Component 9 10 11 12 13 14 15 1617 all amounts in wt % Invention Invention Invention Invention InventionInvention Invention Comp. Comp. a a1 a2 73.3 73.21 73.34 73.44 73.2173.21 73.21 62.58 73.3 a3 a4 a5 a6 a7 a8 a9 4.92 B B1 B2 B3 B4 B5 B6 B7B8 1.49 B9 1.9 B10 1.25 B11 1.67 B12 1.9 B13 1.9 B14 1.9 B15 6.53 B161.94 b1 b3 b4 c c1 0.2 0.73 0.72 d d1 d2 f f1 f2 f3 6.8 6.8 6.8 6.8 6.86.8 6.8 6.82 6.15 f4 f5 f6 f7 17.52 17.2 17.52 17.2 17.2 17.2 17.2 17.5417 g g1 g2 g3 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.88 0.89 g4 g5Formulation Component 18 19 20 21 22 23 24 25 all amount in wt % Comp.acc. to inv. Comp. acc. to inv. Comp. acc. to inv. Comp. acc. to inv. aa1 22 21.9 a2 42.2 42.2 a3 59.89 59.89 a4 95 95 a5 95 95 a6 a7 a8 a94.44 4.44 4.44 4.44 B B1 B2 B3 1.5 1 0.32 B4 B5 0.28 B6 B7 B8 B9 B10 B11B12 B13 B14 B15 B16 b1 0.75 0.5 0.16 0.16 b3 b4 c c1 0.75 0.4 0.4 0.240.4 0.28 d d1 d2 f f1 17.1 17.1 f2 8.84 8.84 15.8 15.8 f3 f4 2.95 2.95 33 f5 f6 f7 9.4 9.4 g g1 14.9 14.9 g2 0.8 0.8 g3 0.32 0.32 0.4 0.4 0 0 00 g4 g5 Formulation Component 26 27 28 29 30 31 all amount in wt % Comp.acc. to inv. Comp. acc. to inv. Comp. acc. to inv. a a1 36 a2 95.6 a362.4 a4 a5 a6 95 95 a7 95 95 a8 3.82 1.04 a9 4.54 4.54 4.84 4.72 B B1 B2B3 B4 B5 0.28 0.28 0.28 B6 B7 B8 B9 B10 B11 B12 B13 B14 B15 B16 b1 0.160.16 0.16 b3 b4 c c1 0.4 0.28 0.3 0.18 d d1 d2 f f1 f2 f3 f4 f5 f6 f7 gg1 g2 g3 0.02 0 0 0 0 0 g4 g5 Formulation Component 32 33 34 35 36 allamount in wt % Comp. Comp. acc. to inv. Comp. acc. to inv. a a1 a2 48.6148.76 48.47 a3 74.19 75.11 a4 a5 a6 a7 a8 1.04 0.94 1.03 a9 B B1 B2 B31.8 B4 B5 0.51 B6 B7 B8 B9 B10 B11 B12 B13 B14 B15 B16 0.59 b1 0.3 0.9b3 0.25 0.25 b4 0.057 0.057 c c1 0.4 0.2 0.18 0.73 d d1 31.84 31.7531.75 d2 0.561 0.5525 0.765 f f1 f2 f3 f4 f5 14.95 14.91 14.95 f6 8.778.75 f7 13.21 13.14 g g1 g2 g3 0.299 0.2975 0.347 0.89 0.89 g4 2 2 2 g51

TABLE 2 Heating temperatures 1st 2nd Housing Carbon black/ housinghousing single- Co- demoulding Test Through- half co- half co- shaftNozzle kneader agent master- arrange- Formula- Carbon black put SpeedPower SME kneader kneader extruder head shaft batch no. ment tionmetering site kg/h min−1 kW kWh/kg ° C. ° C. ° C. ° C. ° C. B1 1 50% b1Feed hopper 1 9 190 3.4 0.378 30 30 40 95 30 50% c1 B2 2 50% b1 Feedhopper 1 12 190 3.3 0.275 90 60 35 130 35 50% c1 B3 3 50% b1 Feed hopper1: 32% 20 250 3.8 0.190 60 35 75 110 35 50% c1 Feed hopper 7: 18% B4 350% b2 Feed hopper 1: 20% 12 250 2.3 0.192 60 35 75 110 35 50% c1 Feedhopper 7: 30%

TABLE 3 Carbon black/ demoulding Test Through- Spec. Heatingtemperatures of the housing parts: agent master- arrange- Formula-Carbon black put Speed power 9 10 11 batch no. ment tion metering sitekg/h min⁻¹ kWh/kg ° C. ° C. ° C. B8 4 50% b1 Feed hopper 8: 25% 25 2000.084 30 60 65 50% c1 Housing part 15: 25% B9 4 40% b1 Feed hopper 8:10% 25 300 0.0096 30 60 65 60% c1 Housing part 15: 30% B10 4 60% b1 Feedhopper 8: 15% 25 200 0.248 30 60 65 40% c1 Housing part 15: 45% B11 445% b1 Feed hopper 8: 10% 25 300 0.037 30 60 65 55% c1 Housing part 15:35% B12 4 40% b1 Feed hopper 8: 20% 25 200 0.032 30 60 65 60% c3 Housingpart 15: 20% B13 4 40% b1 Feed hopper 8: 20% 25 200 0.073 30 60 65 60%c2 Housing part 15: 20% B14 4 40% b1 Feed hopper 8: 20% 25 200 0.073 3060 65 60% c4 Housing part 15: 20% Heating temperatures of the housingparts: Carbon black/ Nozzle demoulding (not agent master- 12 13 14 15 1617 18 19 shown) batch no. ° C. ° C. ° C. ° C. ° C. ° C. ° C. °C. ° C. B865 65 65 70 50 50 50 35 110 B9 65 65 65 70 50 50 50 35 110 B10 65 65 6570 50 50 50 35 130 B11 65 65 65 70 50 50 50 35 110 B12 65 65 65 70 50 5050 35 110 B13 65 65 65 70 50 50 50 35 130 B14 65 65 65 70 50 50 50 35115

TABLE 4 Surface defects Notched impact Notched impact Test Through- percm² strength strength Formula- arrange- put Speed SME Mean of 3 at 23°C. at 0° C. Example tion ment kg/h 1/min kWh/kg sheets kJ/m² kJ/m² 1Comparison 1 7 103 400 0.129 199 46.9 13.75 2 Invention 4 7 97 400 0.13719 50.94 15.09 3 Comparison 18 7 92 400 0.145 53 4 Invention 19 7 92 4000.145 24 5 Comparison 20 8 99 600 0.145 17 12.77 6 Invention 21 8 98 6000.147 11 13.06 7 Comparison 22 7 62 350 0.188 12 8 Invention 23 7 64 3500.182 9 9 Comparison 24 7 62 350 0.188 5 10 Invention 25 7 62 350 0.1884 11 Comparison 28 7 52 350 0.224 257 12 Invention 29 7 52 350 0.224 3413 Comparison 30 7 58 350 0.201 60 14 Invention 31 7 57 350 0.204 31 15Comparison 35 9 20 400 0.247 16 Invention 36 9 20 400 0.24 17 Comparison17 7 73 400 0.131 34 18 Comparison 16 7 73 400 0.131 63 19 Invention 4 775 400 0.133 18 20 Comparison 32 10 3100 187 0.131 2191 21 Comparison 3310 3091 175 0.124 1122 22 Invention 34 10 3092 188 0.131 446 23Comparison 26 11 2975 493 0.141 247 24 Invention 27 11 3003 485 0.132 1125 Invention 10 7 95 400 0.14 6 26 Invention 12 7 95 400 0.14 6 27Invention 9 7 90 400 0.148 10 28 Invention 6 7 95 400 0.14 5 29Invention 11 7 95 400 0.14 5 30 Invention 8 7 90 400 0.148 21 31Invention 7 7 90 400 0.148 11 32 Invention 13 7 90 400 0.148 7 33Invention 14 7 95 400 0.14 48 34 Invention 15 7 95 400 0.14 6 35Invention 5 7 97 400 0.137 23 56.2 19.22 36 Invention 3 7 97 400 0.13719 48.3 16.16 37 Invention 2 7 97 400 0.137 17 52.73 15.93

The invention claimed is:
 1. An injection molded article produced by aprocess comprising preparing injection molding a coloured polymercomposition by melt-mixing, wherein the coloured polymer compositioncomprises a melt-mixed coloured polycarbonate composition, comprising:a) from 40 to 99.96 wt. % of at least one thermoplastic polymer (a),wherein polymer (a) is at least one selected from the group consistingof aromatic polycarbonates and aromatic polyester carbonates, whereinthe polymer (a) has a weight average molecular weight of 15,000 to80,000 g/mol, and wherein the polymer (a) is a homopolycarbonate orcopolycarbonate containing bisphenol A; b) from 0.1 to 3 wt. % of atleast one pigment component (b); c) from 0.1 to 3 wt. % of at least onedemoulding agent (c) selected from the group consisting ofpentaerythritol tetrastearate, glycerol monostearate, and stearylstearate; d) from 0 to 60 wt. % of one or more thermoplastic polyesters(d); e) from 0 to 40 wt. % of one or more elastomers (e) other thancomponent f; f) from 0 to 40 wt. % of one or more optionallyrubber-modified vinyl (co)polymers (f); and g) from 0 to 10 wt. % one ormore further additives; the process comprising using a masterbatch,wherein the melt-mixed coloured polycarbonate composition comprises amasterbatch consists consisting of the at least one pigment (b) and theat least one demoulding agent (c) in compounding prepared using a shearand mixing unit in a single-shaft extruder, a multi-shaft extruder, aninternal mixer, a co-kneader, or a shear roller device, wherein thedemoulding agent is at least one selected from the group consisting ofpentaerythritol tetrastearate, glycerol monostearate and stearylstearate, wherein the at least one pigment is (b) comprises acarbon-based pigment and the content of pigment in the masterbatch isfrom 40 to 60 wt. %, based on the total weight of the masterbatch,wherein the carbon-based pigment is selected from the group consistingof: a) carbon black; b) graphite; c) fullerene; d) graphene; e)activated charcoal; and f) carbon nanotubes, and wherein the processadditionally comprises preparing the masterbatch by using a shear andmixing unit in a single-shaft extruder, multi-shaft extruder, internalmixer, co-kneader or a shear roller device, wherein the pigment ishomogeneously distributed and present in finely dispersed form in thepolymer composition, wherein the produced coloured polymer compositionis a polycarbonate composition comprising a) from 40 to 99.96 wt. % ofat least one thermoplastic polymer (a), wherein polymer (a) is at leastone selected from the group consisting of aromatic polycarbonates andaromatic polyester carbonates, wherein the polymer has a weight averagemolecular weight of 15,000 to 80,000 g/mol and is a homopolycarbonate orcopolycarbonate containing bisphenol A b) from 0.1 to 3 wt. % of atleast one pigment component (b), c) from 0.1 to 3 wt. % of at least onedemoulding agent (c) selected from the group consisting ofpentaerythritol tetrastearate, glycerol monostearate and stearylstearate, d) from 0 to 60 wt. % of one or more thermoplastic polyesters(d), e) from 0 to 40 wt. % of one or more elastomers (e) other thancomponent f, f) from 0 to 40 wt. % of one or more optionallyrubber-modified vinyl (co)polymers (f), and g) from 0 to 10 wt. % one ormore further additives.
 2. An injection molded article according toclaim 1, wherein the pigment is carbon black.
 3. An injection moldedarticle according to claim 1, wherein the masterbatch is prepared by aprocess comprises comprising: a) metering said demoulding agent and saidpigment into said shear and mixing unit, b) melt-mixing the pigment inthe demoulding agent and thereby dispersing the pigment in thedemoulding agent to form a melt mixture, c) optionally filtering themelt mixture, d) forming melt strands, e) cooling and granulating themelt strands, and f) when using underwater or water-ring granulation instep e), drying granules.
 4. The injection molded article according toclaim 3, wherein the granulating is carried out by underwatergranulation or hot-face water-ring granulation.
 5. An injection moldedarticle according to claim 1 wherein said pigment is not in powder form.6. An injection molded article according to claim 1 wherein said pigmentis in the form of a pigment concentrate.
 7. An injection molded articleaccording to claim 1, wherein said masterbatch comprises a concentrateof carbon black in said demoulding agent and said demoulding agent ispentaerythritol tetrastearate.
 8. The injection molded article accordingto claim 1, wherein the coloured polymer composition is a polycarbonatecomposition comprising comprises: a) from 50 to 75 wt. % of at least onethermoplastic polymer (a), b) from 0.1 to 1.5 wt. % of at least onepigment component (b), c) from 0.1 to 1.5 wt. % of at least onedemoulding agent (c), d) from 20 to 60 wt. % of one or morethermoplastic polyesters (d), e) from 2 to 20 wt. % of one or moreelastomers (e) other than component f, f) from 3 to 40 wt. % of one ormore optionally rubber-modified vinyl (co)polymers (f), and g) from 0.2to 10 wt. % one or more further additives.
 9. The injection moldedarticle according to claim 8, wherein the demoulding agent ispentaerythritol tetrastearate.
 10. An injection molded article accordingto claim 1, wherein the demoulding agent is pentaerythitoltetrastearate.
 11. An injection molded article according to claim 1,wherein the masterbatch is used in the form of comprises granules orpellets of 1 to 5 mm in length.
 12. An injection molded articleaccording to claim 1, wherein the masterbatch is used in the form ofcomprises powder having a diameter of 0.1 to 0.5 mm.
 13. An injectionmolded article according to claim 1, wherein the pigment is used in thepreparation of the coloured polymer composition is provided solely inthe form of the masterbatch consisting of pigment and demoulding agent.